This question has unfinished solutions
+ <% end %>
<%= render :partial => "show",
:locals => {:question => @question} %>
<% else %>
diff --git a/app/views/simple_questions/show.1p2.qti.builder b/app/views/simple_questions/show.1p2.qti.builder
index 1bc30bc..ddfdffc 100644
--- a/app/views/simple_questions/show.1p2.qti.builder
+++ b/app/views/simple_questions/show.1p2.qti.builder
@@ -1,20 +1,39 @@
-xml.instruct!
+require 'builder'
+xml = Builder::XmlMarkup.new
-xml.kml(:xmlns => "http://earth.google.com/kml/2.2") {
-xml.Document {
- xml.name("Test")
- xml.open(1)
- xml.visible(1)
- xml.NetworkLink {
- xml.name("My rails app being passed parameters")
- xml.open(1)
- xml.visibility(0)
- xml.Link {
- xml.href("hi")
- xml.viewRefreshMode("onStop")
- xml.viewRefreshTime(0.5)
- xml.viewFormat("BBOX=[bboxWest],[bboxSouth],[bboxEast],[bboxNorth]&CENTRE=[lookatLon],[lookatLat]")
+xml.instruct!
+xml.Document{
+ xml.item{
+ xml.presentation{
+ xml.material{
+ xml.mattext("texttype" => "text/html") {
+ xml.cdata!(@question.content_html.html_safe)
+ }
}
+ xml.response_lid{
+ xml.render_choice{
+ @question.answer_choices.each_index do |ac|
+ xml.response_label("ident" => "A" + ac.to_s){
+ xml.material{
+ xml.mattext("texttype" => "text/html"){
+ xml.cdata!(@question.answer_choices[ac].content_html.html_safe)
+ }
+ }
+ }
+ end
+ }
+ }
+ }
+ xml.resprocessing{
+ @question.answer_choices.each_index do |ac|
+ xml.respcondition{
+ xml.conditionvar{
+ xml.varequal "A" + ac.to_s
+ }
+ xml.setvar(@question.answer_choices[ac].credit,"varname" => "que_score", "action" => "Add"
+ )
+ }
+ end
}
}
-}
\ No newline at end of file
+}
diff --git a/app/views/solutions/_single_solution.html.erb b/app/views/solutions/_single_solution.html.erb
index 524f298..665420a 100644
--- a/app/views/solutions/_single_solution.html.erb
+++ b/app/views/solutions/_single_solution.html.erb
@@ -78,6 +78,9 @@
<% if !solution.explanation.blank? %>
+ <% if !solution.is_visible %>
+
") }
+ rule(:div) { ( div_open >> content >> div_close ).as(:div)}
+
+ #Greek letters
+ rule(:delta) { str("\\xCE\\xB4").as(:delta) }
+ rule(:phi) { str("φ").as(:phi) }
+ rule(:pi) { ( str("π") | str("\\xCF\\x80") ).as(:pi) }
+ rule(:omega) { ( str("ω") | str("\\xCF\\x89") ).as(:omega) }
+ rule(:greek) { delta | phi | pi | omega }
+
+ #Superscripts and Subscripts
+ rule(:sub1) { str("") | str("") }
+ rule(:con) { match(/[a-z|A-Z|0-9]/).repeat(1).as(:con) }
+ rule(:sub2) { str("") | str("") }
+ rule(:sub) { sub1 >> (con | greek | punc.as(:any)).as(:sub) >> sub2 }
+ rule(:sup1) { str("") | str("") }
+ rule(:sup2) { str("") | str("") }
+ rule(:sup) { sup1 >> space? >>(con | greek | punc.as(:any)).repeat.as(:sup) >> sup2 }
+
+
+ #Single character rules
+ rule(:space) { match("\s").repeat(1) }
+ rule(:space?) { space.maybe }
+
+ #Things
+ rule(:letters) { (match(/\w/) >> space?).repeat(1).as(:letters) }
+ rule(:crlf) { match("\r\n") >> space? }
+ rule(:lf) { match("\n") >> space? }
+ rule(:tab) { match("\t") >> space? }
+ rule(:eol) { (crlf | lf | tab).as(:eol) }
+
+ #Grammar parts
+ rule(:punc) { match(/[^<]/) }
+ rule(:tags) { font | pre | span | div | image | link_full }
+ rule(:format) { italic_tag | bold_tag | line_break | tt_tag | sub | sup | center | entities | exclamation | code }
+ rule(:text) { ( tags | format | letters | eol | new_p | greek | entities | lthan | gthan | (any.as(:any)) ).repeat(1) }
+ rule(:ques) { text.repeat.as(:text) }
+
+ rule(:expression) { ques }
+ root :expression
+end
+
+#class UnavailableImage < StandardError; end
+
+class SPQRTransform < Parslet::Transform
+ rule(:image => sequence(:image)) { "\[MISSING IMAGE: #{image[0].to_s}\]"}
+ rule(:filename => simple(:filename)) { filename.str.gsub(/[\n\t]/, "").strip }
+ rule(:address => simple(:address)) { "\[LINK TO: #{address.to_s}\] "}
+ rule(:link_name => simple(:link_name)) { link_name }
+ rule(:link_info => simple(:link_info)) { link_info }
+ rule(:link_info => sequence(:info)) { info.join }
+ rule(:italic => simple(:italic)) {"''"}
+ rule(:bold => simple(:bold)) {"!!"}
+ rule(:line_break => simple(:break)) {"\n"}
+ rule(:ttype => simple(:ttype)) {"$"}
+ rule(:para => simple(:para)) {"\n\n"}
+ rule(:center => simple(:center)) {}
+ rule(:code => simple(:code)) {}
+ rule(:exclamation => simple(:exclamation)) {"!"}
+ rule(:asterisk => simple(:asterisk)) {'×'}
+ rule(:lthan => simple(:lthan)) {'<'}
+ rule(:gthan => simple(:gthan)) {'>'}
+ rule(:apos => simple(:apos)) {'''}
+ rule(:quote1 => simple(:quote1)) {'"'}
+ rule(:dollar => simple(:dollar)) {'$'}
+ rule(:pound => simple(:pound)) {'£'}
+ rule(:content_f => sequence(:content_f)) {"''" + content_f.join + "''"}
+ rule(:font => simple(:font)) { font }
+ rule(:content_p => sequence(:content_p)) {"$$" + content_p.join + "$$"}
+ rule(:pre => simple(:pre)) { pre }
+ rule(:content => sequence(:content)) { content.join}
+ rule(:span => simple(:span)) { span }
+ rule(:div => simple(:div)) { div }
+ rule(:delta => simple(:delta)) {"\\delta"}
+ rule(:phi => simple(:phi)) {"\\phi"}
+ rule(:pi => simple(:pi)) {"\\pi"}
+ rule(:omega => simple(:omega)) {"\\omega"}
+ rule(:con => simple(:con)) { con }
+ rule(:sub => simple(:sub)) {"_{" + sub + "}"}
+ rule(:sup => sequence(:sup)) {"^{" + sup.join + "}"}
+ rule(:letters => simple(:letters)) { letters }
+ rule(:eol => simple(:eol)) {}
+ rule(:any => simple(:any)) { any }
+ rule(:text => sequence(:entries)) { entries.join }
+end
diff --git a/lib/test_import.rb b/lib/test_import.rb
new file mode 100644
index 0000000..96f2b98
--- /dev/null
+++ b/lib/test_import.rb
@@ -0,0 +1,136 @@
+#encoding: utf-8
+
+# Copyright 2011-2012 Rice University. Licensed under the Affero General Public
+# License version 3 or later. See the COPYRIGHT file for details.
+
+require 'open-uri'
+require 'spqr_parser.rb'
+
+class TestImport
+
+ @@content_types = [['SPQR','SPQR']]
+
+ attr_reader :filename, :content_type, :parser, :transformer
+
+ def self.content_types
+ @@content_types
+ end
+
+ def self.choose_import(content_type)
+ if (content_type == 'SPQR')
+ a = SPQRParser.new
+ b = SPQRTransform.new
+ end
+ return a, b
+ end
+
+ def self.createproject(current_user)
+ a = Project.create(:name => 'Import')
+ # a.add_member!(current_user)
+ a
+ end
+
+ def self.get_credit(content)
+ credit = Hash.new
+ for a in 0..(content.length-1)
+ b = content[a].children.children[1].children[0]
+ label = b.content
+ c = content[a].children.children.last
+ d = (c.content).to_f
+ if d < 0
+ d = 0
+ end
+ credit[label] = d
+ end
+ return credit
+ end
+
+ def self.get_questions(project, content, parser, transformer,current_user)
+ ques_nodes = content.xpath('//presentation')
+ # ans_nodes = content.xpath('//presentation//response_lid//response_label')
+ credit_nodes = content.xpath('//resprocessing//respcondition')
+ credit = get_credit(credit_nodes)
+ # answers = self.get_answers(ans_nodes,credit_nodes,parser,transformer)
+ for a in 0..(content.length-1)
+ b = content[a]
+ ques_id = b.attributes["ident"].value
+ c = ques_nodes[a].children.children.children
+ text = c[0].content
+ d = parser.parse(text)
+ ques = transformer.apply(d)
+ q = SimpleQuestion.new(:content => ques)
+ q.save!
+ e = Comment.new(:message => ques_id)
+ e.comment_thread = q.comment_thread
+ e.creator = current_user
+ e.save!
+ temp_ans = Array.new
+ temp_credit = Array.new
+ f = content[a].xpath('//response_lid//response_label')
+ for g in 0..(f.length-1)
+ label = f[g].attributes["ident"].value
+ temp_credit << credit[label]
+ h = f[g].children.children.children
+ text = h[0].content
+ i = parser.parse(text)
+ ans = transformer.apply(i)
+ temp_ans << ans
+ end
+ # for f in 0..(answers.keys.length-1)
+ # k = answers.keys[f]
+ # if k.match(ques_id) != nil
+ # temp_ans << answers[k]
+ # end
+ # end
+ # answers.each_key {|j| if j.match(ques_id) then answers.delete(j) end }
+ if temp_ans.length == 0
+ temp_ans << 'fake'
+ temp_credit << 0
+ temp_ans << 'not real'
+ temp_credit << 1
+ elsif temp_ans.length == 1
+ temp_ans << 'fake'
+ temp_credit << 0
+ end
+ # for g in 0..(temp_ans.length-1)
+ # temp_credit << temp_ans[g][1]
+ # end
+ points = self.normalize(temp_credit)
+ if points.max == 0
+ temp_ans << 'fake'
+ points << 1.0
+ end
+ for i in 0..(temp_ans.length-1)
+ q.answer_choices << AnswerChoice.new(:content => temp_ans[i], :credit => temp_credit[i])
+ end
+ q.save!
+ project.add_question!(q)
+ end
+ end
+
+#For the SPQR content, it seems that a series of questions are embedded
+#within each This solution is not ready to be viewed.
+ <% end %>
High-Level Explanation
<%= simple_format solution.explanation %>
diff --git a/app/views/users/action_new.js.erb b/app/views/users/action_new.js.erb
index ab22a75..8ab4106 100644
--- a/app/views/users/action_new.js.erb
+++ b/app/views/users/action_new.js.erb
@@ -11,4 +11,4 @@ $("#user_action_dialog").dialog({
width:600,
buttons: { "Close": function() { $(this).dialog("close"); }},
open: function(event, ui) { $("#text_query").val(''); $("#selected_type").val(''); }
-});
\ No newline at end of file
+}).closeOnClickOutside();
diff --git a/config/application.rb b/config/application.rb
index 12ca276..8e69815 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -1,3 +1,5 @@
+#encoding: utf-8
+
# Copyright 2011-2012 Rice University. Licensed under the Affero General Public
# License version 3 or later. See the COPYRIGHT file for details.
diff --git a/config/environment.rb b/config/environment.rb
index 2bdcbce..b2948b0 100644
--- a/config/environment.rb
+++ b/config/environment.rb
@@ -1,3 +1,5 @@
+#encoding: utf-8
+
# Copyright 2011-2012 Rice University. Licensed under the Affero General Public
# License version 3 or later. See the COPYRIGHT file for details.
@@ -14,8 +16,13 @@
require 'form_builder_extensions'
require 'acts_as_numberable'
require 'variated_content_html'
+require 'spqr_parser'
+require 'qti_import'
+
ActionMailer::Base.delivery_method = :sendmail
+Encoding.default_external = Encoding::UTF_8
+Encoding.default_internal = Encoding::UTF_8
# Initialize the rails application
Quadbase::Application.initialize!
diff --git a/config/initializers/carrierwave.rb b/config/initializers/carrierwave.rb
new file mode 100644
index 0000000..7f4a20b
--- /dev/null
+++ b/config/initializers/carrierwave.rb
@@ -0,0 +1,5 @@
+if Rails.env.test?
+ CarrierWave.configure do |config|
+ config.storage = :file
+ end
+end
\ No newline at end of file
diff --git a/config/routes.rb b/config/routes.rb
index a4e0518..ec94b11 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -3,6 +3,9 @@
Quadbase::Application.routes.draw do
+ get "/import/qti/new", :to => 'qt_import#new'
+ post "/import/qti", :to => 'qt_import#create'
+
namespace :admin do
resources :logic_libraries do
resources :logic_library_versions, :shallow => true
diff --git a/db/migrate/20120613190208_create_file_uploads.rb b/db/migrate/20120613190208_create_file_uploads.rb
new file mode 100644
index 0000000..6736a71
--- /dev/null
+++ b/db/migrate/20120613190208_create_file_uploads.rb
@@ -0,0 +1,12 @@
+class CreateFileUploads < ActiveRecord::Migration
+ def self.up
+ create_table :file_uploads do |t|
+
+ t.timestamps
+ end
+ end
+
+ def self.down
+ drop_table :file_uploads
+ end
+end
diff --git a/db/migrate/20120717032712_remove_image_answer_from_question.rb b/db/migrate/20120717032712_remove_image_answer_from_question.rb
new file mode 100644
index 0000000..825fc7b
--- /dev/null
+++ b/db/migrate/20120717032712_remove_image_answer_from_question.rb
@@ -0,0 +1,9 @@
+class RemoveImageAnswerFromQuestion < ActiveRecord::Migration
+ def up
+ remove_column :questions, :image_answer
+ end
+
+ def down
+ add_column :questions, :image_answer, :string
+ end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 0d37c5b..f34a207 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -18,16 +18,16 @@
t.text "subject"
t.text "body"
t.boolean "force"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "answer_choices", :force => true do |t|
t.integer "question_id"
t.text "content"
t.decimal "credit"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.text "content_html", :limit => 255
end
@@ -37,16 +37,16 @@
t.integer "attachment_file_size"
t.datetime "attachment_updated_at"
t.integer "uploader_id"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "attachable_assets", :force => true do |t|
t.integer "attachable_id"
t.integer "asset_id"
t.string "local_name"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.text "description"
t.string "attachable_type"
end
@@ -54,16 +54,16 @@
create_table "comment_thread_subscriptions", :force => true do |t|
t.integer "comment_thread_id"
t.integer "user_id"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.integer "unread_count", :default => 0
end
create_table "comment_threads", :force => true do |t|
t.string "commentable_type"
t.integer "commentable_id"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "comments", :force => true do |t|
@@ -71,23 +71,28 @@
t.text "message"
t.integer "creator_id"
t.boolean "is_log"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "deputizations", :force => true do |t|
t.integer "deputizer_id"
t.integer "deputy_id"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
+ end
+
+ create_table "file_uploads", :force => true do |t|
+ t.datetime "created_at", :null => false
+ t.datetime "updated_at", :null => false
end
create_table "licenses", :force => true do |t|
t.string "short_name"
t.string "long_name"
t.string "url"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.string "agreement_partial_name"
t.boolean "is_default"
end
@@ -96,8 +101,8 @@
t.string "name"
t.integer "number"
t.text "summary"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.boolean "always_required"
end
@@ -107,8 +112,8 @@
t.text "code"
t.text "minified_code"
t.boolean "deprecated"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "logics", :force => true do |t|
@@ -116,8 +121,8 @@
t.string "variables"
t.string "logicable_type"
t.integer "logicable_id"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.text "cached_code"
t.string "variables_array"
t.string "required_logic_library_version_ids"
@@ -125,29 +130,29 @@
create_table "messages", :force => true do |t|
t.string "subject"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "project_members", :force => true do |t|
t.integer "project_id"
t.integer "user_id"
t.boolean "is_default"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "project_questions", :force => true do |t|
t.integer "project_id"
t.integer "question_id"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "projects", :force => true do |t|
t.string "name"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "question_collaborators", :force => true do |t|
@@ -156,8 +161,8 @@
t.integer "position"
t.boolean "is_author", :default => false
t.boolean "is_copyright_holder", :default => false
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.integer "question_role_requests_count", :default => 0
end
@@ -165,24 +170,31 @@
t.integer "independent_question_id"
t.integer "dependent_question_id"
t.string "kind"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "question_derivations", :force => true do |t|
t.integer "derived_question_id"
t.integer "source_question_id"
t.integer "deriver_id"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
+ end
+
+ create_table "question_imports", :force => true do |t|
+ t.string "File"
+ t.string "ContentType"
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "question_parts", :force => true do |t|
t.integer "multipart_question_id"
t.integer "child_question_id"
t.integer "order"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "question_role_requests", :force => true do |t|
@@ -190,16 +202,16 @@
t.boolean "toggle_is_author"
t.boolean "toggle_is_copyright_holder"
t.integer "requestor_id"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.boolean "is_approved", :default => false
t.boolean "is_accepted", :default => false
end
create_table "question_setups", :force => true do |t|
t.text "content"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.text "content_html", :limit => 255
end
@@ -209,8 +221,8 @@
t.string "question_type"
t.text "content"
t.integer "question_setup_id"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.integer "license_id"
t.text "content_html", :limit => 255
t.integer "locked_by", :default => -1
@@ -226,8 +238,8 @@
t.integer "creator_id"
t.text "content"
t.integer "question_id"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.text "content_html"
t.text "explanation"
t.boolean "is_visible"
@@ -254,37 +266,36 @@
t.integer "user_id"
t.boolean "project_member_email", :default => true
t.boolean "role_request_email", :default => true
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.boolean "announcement_email"
t.boolean "auto_author_subscribe", :default => true
end
create_table "users", :force => true do |t|
- t.string "email", :default => "", :null => false
- t.string "encrypted_password", :default => "", :null => false
+ t.string "email", :default => "", :null => false
+ t.string "encrypted_password", :limit => 128, :default => "", :null => false
t.string "reset_password_token"
- t.datetime "reset_password_sent_at"
t.datetime "remember_created_at"
- t.integer "sign_in_count", :default => 0
+ t.integer "sign_in_count", :default => 0
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
+ t.integer "failed_attempts", :default => 0
+ t.string "unlock_token"
+ t.datetime "locked_at"
t.string "confirmation_token"
t.datetime "confirmed_at"
t.datetime "confirmation_sent_at"
- t.integer "failed_attempts", :default => 0
- t.string "unlock_token"
- t.datetime "locked_at"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
t.string "first_name"
t.string "last_name"
- t.boolean "is_administrator", :default => false
+ t.boolean "is_administrator", :default => false
t.string "username"
t.datetime "disabled_at"
- t.integer "unread_message_count", :default => 0
+ t.integer "unread_message_count", :default => 0
end
add_index "users", ["confirmation_token"], :name => "index_users_on_confirmation_token", :unique => true
@@ -297,16 +308,16 @@
t.boolean "thumbs_up"
t.string "votable_type"
t.integer "votable_id"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
create_table "website_configurations", :force => true do |t|
t.string "name"
t.string "value"
t.string "value_type"
- t.datetime "created_at", :null => false
- t.datetime "updated_at", :null => false
+ t.datetime "created_at"
+ t.datetime "updated_at"
end
end
diff --git a/lib/asset_methods.rb b/lib/asset_methods.rb
index e6e94a9..8dad4bd 100644
--- a/lib/asset_methods.rb
+++ b/lib/asset_methods.rb
@@ -8,7 +8,7 @@ def get_image_tag_maker
end
def get_asset(local_name)
- attachable_assets.select{|aa| aa.local_name == local_name}.first.asset
+ attachable_assets.select{|aa| aa.local_name == local_name}.first.try(:asset)
end
-end
\ No newline at end of file
+end
diff --git a/lib/image_tag_maker.rb b/lib/image_tag_maker.rb
index 2cd9883..bcaa803 100644
--- a/lib/image_tag_maker.rb
+++ b/lib/image_tag_maker.rb
@@ -9,7 +9,12 @@ def initialize(attachable)
def make_tag(image_name)
url = Rails.env.production? ? "https" : "http"
url += "://#{Rails.application.config.default_url_options[:host]}/"
- url += "#{@attachable.get_asset(image_name).path(:medium)}"
- "![](\"#{url}\")
"
+ asset_got = @attachable.get_asset(image_name)
+ if !asset_got.nil?
+ url += asset_got.path(:medium)
+ ""
+ else
+ "#{image_name}"
+ end
end
end
diff --git a/lib/learning_parser.rb b/lib/learning_parser.rb
new file mode 100644
index 0000000..86d0255
--- /dev/null
+++ b/lib/learning_parser.rb
@@ -0,0 +1,41 @@
+# encoding: utf-8
+require 'parslet'
+
+class Mini < Parslet::Parser
+ #Single character rules
+ rule(:lparen) { str('(') >> space? }
+ rule(:rparen) { str(')') >> space? }
+ rule(:comma) { str(',') >> space? }
+
+ rule(:space) { match('\s').repeat(1) }
+ rule(:space?) { space.maybe }
+
+ #Things
+ rule(:integer) { match('[0-9]').repeat(1).as(:int) >> space?}
+ rule(:identifier) { match['a-z'].repeat(1) }
+ rule(:operator) { match('[+]') >> space? }
+
+ #Grammar parts
+ rule(:sum) { integer.as(:left) >> operator.as(:op) >> expression.as(:right) }
+ rule(:arglist) { expression >> (comma >> expression).repeat }
+ rule(:funcall) { identifier.as(:funcall) >> lparen >> arglist.as(:arglist) >> rparen }
+
+
+ rule(:expression) { funcall | sum | integer }
+ root :expression
+end
+
+
+def parse(str)
+ mini = Mini.new
+ print "Parsing #{str}: "
+
+ p mini.parse(str)
+
+ rescue Exception
+ puts "Sorry, but " + str + " contains non-ASCII characters. Please replace with the correct formatting."
+end
+
+parse 'puts(1 + 2 + 3)'
+
+
diff --git a/lib/qti_import.rb b/lib/qti_import.rb
new file mode 100644
index 0000000..decaf2f
--- /dev/null
+++ b/lib/qti_import.rb
@@ -0,0 +1,131 @@
+#encoding: utf-8
+
+# Copyright 2011-2012 Rice University. Licensed under the Affero General Public
+# License version 3 or later. See the COPYRIGHT file for details.
+
+require 'htmlentities'
+require 'open-uri'
+require 'spqr_parser.rb'
+
+class QTImport
+
+ @@content_types = [['SPQR']]
+
+ attr_reader :filename, :content_type, :parser, :transformer
+
+ def self.content_types
+ @@content_types
+ end
+
+ def self.choose_import(content_type)
+ if (content_type == 'SPQR')
+ a = SPQRParser.new
+ b = SPQRTransform.new
+ end
+ return a, b
+ end
+
+ def self.createproject(current_user)
+ a = Project.create(:name => 'Import')
+ a.add_member!(current_user)
+ a
+ end
+
+ def self.get_credit(content)
+ credit = Hash.new
+ for a in 0..(content.length-1)
+ b = content[a].children.children[1].children[0]
+ label = b.content
+ c = content[a].children.children.last
+ d = (c.content).to_f
+ if d < 0
+ d = 0
+ end
+ credit[label] = d
+ end
+ return credit
+ end
+
+ def self.get_questions(project, content, parser, transformer,current_user)
+ coder = HTMLEntities.new
+ ques_nodes = content.xpath('//presentation')
+ credit_nodes = content.xpath('//resprocessing//respcondition')
+ credit = get_credit(credit_nodes)
+ for a in 0..(content.length-1)
+ b = content[a]
+ ques_id = b.attributes["ident"].value
+ c = ques_nodes[a].children.children.children
+ text = c[0].content
+ text = coder.decode(text)
+ d = parser.parse(text)
+ ques = transformer.apply(d)
+ q = SimpleQuestion.new(:content => ques)
+ q.save!
+ e = Comment.new(:message => ques_id)
+ e.comment_thread = q.comment_thread
+ e.creator = current_user
+ e.save!
+ temp_ans = Array.new
+ temp_credit = Array.new
+ f = content[a].xpath('.//response_lid//response_label')
+ for g in 0..(f.length-1)
+ label = f[g].attributes["ident"].value
+ temp_credit << credit[label]
+ h = f[g].children.children.children
+ text = h[0].content
+ text = coder.decode(text)
+ i = parser.parse(text)
+ ans = transformer.apply(i)
+ temp_ans << ans
+ end
+ if temp_ans.length == 0
+ temp_ans << 'fake'
+ temp_credit << 0
+ temp_ans << 'not real'
+ temp_credit << 1
+ elsif temp_ans.length == 1
+ temp_ans << 'fake'
+ temp_credit << 0
+ end
+ points = self.normalize(temp_credit)
+ if points.max == 0
+ temp_ans << 'fake'
+ points << 1.0
+ end
+ for j in 0..(temp_ans.length-1)
+ q.answer_choices << AnswerChoice.new(:content => temp_ans[j], :credit => temp_credit[j])
+ end
+ q.save!
+ project.add_question!(q)
+ end
+ end
+
+
+#For the SPQR content, it seems that a series of questions are embedded
+#within each  }
+ rule(:image_end_tag) { str(')
') }
+ rule(:image) { (image_start_tag >> ( filename >> image_end_tag ).repeat(1)).as(:image) }
+
+ #Check for formatting
+ rule(:italic_tag) { (str("") | str("") | str("") | str("")).as(:italic) }
+ rule(:bold_tag) { (str("") | str("") | str("") | str("")).as(:bold) }
+ rule(:line_break) { (str("
") | str("
")).as(:line_break) } + rule(:tt_tag) { (str("") | str("") | str("") | str("")).as(:ttype)} + rule(:new_p) { (str("")}
+ rule(:font_open) { (font1 >> (extra_f >> font2).repeat(1)) }
+ rule(:content_f) { match(/[a-z|A-Z|0-9|\/|\-|\.|\?|\s|\\|\n|\t|\"|=]/).repeat(1).as(:content_f) }
+ rule(:font_close) { str("") }
+ rule(:font) { ( font_open >> (content_f >> font_close).repeat(1) ).as(:font) }
+
+ #check for any special classes
+ rule(:pre1) { str("") }
+ rule(:pre_open) { (pre1 >> (extra_p >> pre2).repeat(1)) }
+ rule(:content_p) { match(/[a-z|A-Z|0-9|\/|\-|\.|\?|\s|\\|\n|\t|\"|=]/).repeat(1).as(:content_p) }
+ rule(:pre_close) { str("") | str("") }
+ rule(:pre) { (pre_open >> (content_p >> pre_close).repeat(1) ).as(:pre) }
+
+ #Single character rules
+ rule(:space) { match("\s").repeat(1) }
+ rule(:space?) { space.maybe }
+
+ #Things
+ rule(:letters) { (match(/\w/) >> space?).repeat(1).as(:letters) }
+ rule(:crlf) { match("\r\n") >> space? }
+ rule(:lf) { match("\n") >> space? }
+ rule(:tab) { match("\t") >> space? }
+ rule(:eol) { (crlf | lf | tab).as(:eol) }
+
+ #Grammar parts
+ rule(:format) { italic_tag | bold_tag | line_break | tt_tag | font | pre }
+ rule(:text) { ( image | format | letters | eol | new_p | (any.as(:any)) ).repeat(1) }
+ rule(:ques) { text.repeat(1).as(:text) }
+
+ rule(:expression) { ques }
+ root :expression
+end
+
+class UnavailableImage < StandardError; end
+
+class QTITransform < Parslet::Transform
+ rule(:italic => simple(:italic)) {"'"}
+ rule(:bold => simple(:bold)) {"!!"}
+ rule(:line_break => simple(:break)) {"\n"}
+ rule(:ttype => simple(:ttype)) {"$"}
+ rule(:para => simple(:para)) {"\n\n"}
+ rule(:eol => simple(:eol)) { eol }
+ rule(:content_f => simple(:content_f)) {"!!" + content_f + "!!"}
+ rule(:font => sequence(:font)) {"#{font[0].to_s}"}
+ rule(:letters => simple(:letters)) { letters }
+ rule(:any => simple(:any)) { any }
+ rule(:image => sequence(:parts)) { raise UnavailableImage, "Image #{parts[0].to_s} must be uploaded"}
+ rule(:filename => simple(:filename)) { filename.str.gsub(/[\n\t]/, "").strip }
+ rule(:text => sequence(:entries)) { entries.join }
+end
diff --git a/lib/quadbase_markup.rb b/lib/quadbase_markup.rb
index ab19aaa..2cc0760 100644
--- a/lib/quadbase_markup.rb
+++ b/lib/quadbase_markup.rb
@@ -9,6 +9,8 @@ class QuadbaseParser < Parslet::Parser
def parse(str)
# Always make sure we have one 'paragraph'
super(str.strip + "\n\n")
+
+
end
# TODO add \# and \* as allowed in text
@@ -16,7 +18,7 @@ def parse(str)
root(:paragraphs)
rule(:paragraphs) { paragraph.repeat.as(:paragraphs) }
- rule(:paragraph) { (( line | bulleted_list | numbered_list ).repeat(1) >> spaces >> eol).as(:paragraph) }
+ rule(:paragraph) { (( line | bulleted_list | numbered_list ).repeat >> spaces >> eol).as(:paragraph) }
rule(:line) { (content >> eol).as(:line) }
rule(:content) { (math | image | bold | italic | underline | text).repeat(1) }
@@ -39,14 +41,14 @@ def parse(str)
).repeat(1).as(:text) }
rule(:bold_tag) { str("!!") }
- rule(:bold) { bold_tag >> content.as(:bold) >> bold_tag }
+ rule(:bold) { bold_tag >> ( ( content | eol ).repeat(1) ).as(:bold) >> bold_tag }
rule(:italic_tag) { str("''") }
- rule(:italic) { italic_tag >> content.as(:italic) >> italic_tag }
+ rule(:italic) { italic_tag >> ( ( content | eol ).repeat(1) ).as(:italic) >> italic_tag }
rule(:underline_tag) {str("__") }
rule(:underline) {underline_tag >> content.as(:underline) >> underline_tag }
-
+
rule(:bullet_tag) { str("*") }
rule(:bullet) { bullet_tag >> spaces >> content.as(:bullet) }
rule(:bulleted_list) { (bullet >> eol).repeat(1).as(:bulleted_list) }
@@ -116,6 +118,7 @@ class QuadbaseHtmlTransformer < Parslet::Transform
rule(:text => simple(:text)) { "#{text}" }
rule(:line => sequence(:entries)) { entries.join }
rule(:paragraph => sequence(:entries)) { "" + TagHelper.make_image_tag(filename) + " " }
diff --git a/lib/sample_QTI_questions.xml b/lib/sample_QTI_questions.xml
new file mode 100644
index 0000000..70d9bef
--- /dev/null
+++ b/lib/sample_QTI_questions.xml
@@ -0,0 +1,24 @@
+# Copyright 2011-2012 Rice University. Licensed under the Affero General Public
+# License version 3 or later. See the COPYRIGHT file for details.
+
+
fs = 11025;
tt = (0:round(0.25*fs + ))/fs;
Which MATLAB code would you use to gene +rate the appropriate DTMF signal to represent telephone key number + 5? And this is another way.]]> + + + + φ) for the followi + ng sinusoid where
% Returns a single sinusoid with the key and duration specified
fs = 11025;
tt = 0:1/fs:dur;
f0 = 440*2^((keynum-49)/12);
tone = cos(2*pi*f0*tt);
fs = 11025;
tt = (0:round(0.25*fs + ))/fs;
Which MATLAB code would you use to gene +rate the appropriate DTMF signal to represent telephone key number + 5? And this is another way.]]> + + + + φ) for the followi + ng sinusoid where
% Returns a single sinusoid with the key and duration specified
fs = 11025;
tt = 0:1/fs:dur;
f0 = 440*2^((keynum-49)/12);
tone = cos(2*pi*f0*tt);') }
+ rule(:quote) { str('"')}
+ rule(:attribute_con) { match(/[a-z|A-Z|0-9|\/|\-|\.|\?|\s|\\|\n|\t|\_|\{|\}|=]/)}
+ rule(:attribute) { attribute_con >> quote >> attribute_con >> quote }
+ rule(:image) { (image_start_tag >> space? >> (( file | attribute ).repeat(1)) >> space? >> image_end_tag.maybe ).as(:image) }
+
+ #Check for any external links
+ rule(:link1) { str("") }
+ rule(:address) { match(/[a-z|A-Z|0-9|\/|\-|\.|\?|\s|\\|\n|\t|\_|\{|\}|=|]/).repeat(1).as(:address) }
+ rule(:link_info) { space? >> str("href=") >> quote.maybe >> address >> quote.maybe }
+ rule(:link) { (link1 >> space? >> (( link_info | attribute).repeat(1)) >> space? >> link2.maybe ) }
+ rule(:link_name) { match(/[a-z|A-Z|0-9|\/|\-|\.|\?|\s|\\|\n|\t|\_|\{|\}|=|\"]/).repeat(1).as(:link_name) }
+ rule(:link_end) { str("") | str("") }
+ rule(:link_full) { ( link >> link_name.maybe >> link_end ).as(:link_info)}
+
+ #Check for formatting
+ rule(:italic_tag) { (str("") | str("") | str("") | str("")).as(:italic) }
+ rule(:bold_tag) { (str("") | str("") | str("") | str("")).as(:bold) }
+ rule(:line_break) { (str("
") | str("
")).as(:line_break) } + rule(:tt_tag) { (str("") | str("") | str("") | str("")).as(:ttype)} + rule(:new_p) { (str("") | str(" ") | str("") | str(" ")).as(:center)}
+ rule(:code) { (str("")}
+ rule(:font_open) { font1 >> extra.maybe >> font2 }
+ rule(:content_f) { ( tags | format | letters | eol | new_p | greek | (punc.as(:any)) ).repeat.as(:content_f) }
+ rule(:font_close) { str("") | str("") }
+ rule(:font) { ( font_open >> content_f >> font_close ).as(:font) }
+
+ #Check for any special display classes
+ rule(:pre1) { str("") }
+ rule(:pre_open) { pre1 >> extra.maybe >> pre2 }
+ rule(:content_p) { ( tags | format | letters | eol | new_p | greek | (punc.as(:any)) ).repeat.as(:content_p) }
+ rule(:pre_close) { str("") | str("") }
+ rule(:pre) { ( pre_open >> content_p >> pre_close ).as(:pre) }
+
+ rule(:span1) { str("") }
+ rule(:span_open) { span1 >> extra.maybe >> span2 }
+ rule(:content) { ( tags | format | letters | eol | new_p | greek | (punc.as(:any)) ).repeat.as(:content) }
+ rule(:span_close) { str("") | str("") }
+ rule(:span) { ( span_open >> content >> span_close ).as(:span) }
+
+ rule(:div1) { str("") }
+ rule(:div_open) { div1 >> extra.maybe >> div2 }
+ rule(:div_close) { str("
") | str("") | str("
")).as(:line_break) } + rule(:tt_tag) { (str("") | str("") | str("") | str("")).as(:ttype)} + rule(:new_p) { (str("
") | str("
") | str("") | str("
")).as(:para)} + + #Check for any font changes + rule(:font1) { str("#{entries.join}
" } + rule(:paragraph => simple(:paragraph)) { "\n" } rule(:paragraphs => sequence(:entries)) { entries.join("\n") } rule(:filename => simple(:filename)) { "#{filename}" } rule(:image => simple(:filename)) { "fs = 11025;
tt = (0:round(0.25*fs + ))/fs;
Which MATLAB code would you use to gene +rate the appropriate DTMF signal to represent telephone key number + 5? And this is another way.]]> + + + + φ) for the followi + ng sinusoid where
x(t) = cos(ωt + φ); +]]> + + function tone=note(keynum,dur)
% Returns a single sinusoid with the key and duration specified
fs = 11025;
tt = 0:1/fs:dur;
f0 = 440*2^((keynum-49)/12);
tone = cos(2*pi*f0*tt);
A student wants to modify the function so that the tone created by this function has TWO frequency components. The new tone should be the sum of two sinusoids, one of which is the fundamental and the other of which has a frequency 2 times higher. The amplitudes (and phases) can be the same. Which one of the following is a correct modification that will accomplish this task? +]]> + +x(t) = e2cos(5πt)cos(2πfct)Determine fc.]]> + +ƒ0 = 13.4 Hz. Determine the smallest integer value of the sampling rate ƒs so that no aliasing occurs. The units of ƒs are samples per second. You must justify your response by citing a theorem or property about sampling.]]> + +Folded Alias: Set the input frequency to ƒ0 = 13 Hz, the input phase to φ = -1.3 rads, and ƒs = 20 Hz. Write down the formula for the output signal, and then write a justification consisting of three steps:
- calculating the values of
for the blue spectral lines in the spectrum of the discrete-time signal x[n] shown in the middle plots,
- aliasing
- transforming x[n] into y(t) using an equation that describes the ideal D-to-C converter and uses the principal aias.
fs = 11025;
tt = (0:round(0.25*fs + ))/fs;
Which MATLAB code would you use to gene +rate the appropriate DTMF signal to represent telephone key number + 5? And this is another way.]]> + + + + φ) for the followi + ng sinusoid where
x(t) = cos(ωt + φ); +]]> + + function tone=note(keynum,dur)
% Returns a single sinusoid with the key and duration specified
fs = 11025;
tt = 0:1/fs:dur;
f0 = 440*2^((keynum-49)/12);
tone = cos(2*pi*f0*tt);
A student wants to modify the function so that the tone created by this function has TWO frequency components. The new tone should be the sum of two sinusoids, one of which is the fundamental and the other of which has a frequency 2 times higher. The amplitudes (and phases) can be the same. Which one of the following is a correct modification that will accomplish this task? +]]> + +x(t) = e2cos(5πt)cos(2πfct)Determine fc.]]> + +ƒ0 = 13.4 Hz. Determine the smallest integer value of the sampling rate ƒs so that no aliasing occurs. The units of ƒs are samples per second. You must justify your response by citing a theorem or property about sampling.]]> + +Folded Alias: Set the input frequency to ƒ0 = 13 Hz, the input phase to φ = -1.3 rads, and ƒs = 20 Hz. Write down the formula for the output signal, and then write a justification consisting of three steps:
- calculating the values of
- aliasing
- transforming x[n] into y(t) using an equation that describes the ideal D-to-C converter and uses the principal aias.
") | str("
")).as(:line_break) } + rule(:tt_tag) { (str("") | str("") | str("") | str("")).as(:ttype)} + rule(:new_p) { (str("
") | str("
") | str("") | str("
")).as(:para)} + rule(:center) { (str("") | str("") | str("") | str("")).as(:code)}
+
+ #Two exclamation points in a row signifiy a bold tag, so those should be changed to avoid confusion.
+ rule(:exclamation) { str("!!").repeat(1).as(:exclamation) }
+
+ #Things to be changed to HTML entities
+ rule(:asterisk) { str("*").as(:asterisk)}
+ rule(:lthan) { str("<").as(:lthan) }
+ rule(:gthan) { str(">").as(:gthan) }
+ rule(:apos) { str("'").as(:apos) }
+ rule(:quote1) { str('"').as(:quote1)}
+ rule(:dollar) { str("$").as(:dollar) }
+ rule(:pound) { str("\#").as(:pound) }
+ rule(:entities) { asterisk | apos | quote1 | dollar | pound }
+
+ #Check for any font changes
+ rule(:font1) { str("fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
into another domain where signals can be representd by polynomials and systems can be
represented by rational functions. This transformation greatly simplifies signal manipulation
and filter design. ]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Assuming that the filter was designed via the Hamming-sinc formula, which one of the following can display the values of all the passband frequencies? The passband is defined as same as Bandpass Filters lab. ]]>
Which coefficient is equal to -1? ]]>
Since x[n] is a discrete-time sinusoid, its spectrum will contain an infinite number of lines in the omega-hat domain. Select the location of two of these omega-hat frequencies (in radians). + +]]>
Find H(ejω) where ω is the normalized frequency called "omega-hat" in the text.
]]>Each string row vector is an array of characters ('0' or '1') in MATLAB, e.g., '0010110101110'. + +
Which of the following is the correct way +to form the bit string sent out from modem? +]]>
Mark ALL the correct solutions. +]]>
HH=freqz(hh,1,ww);
plot(ww,abs(HH)) ]]>
HH=freqz(ww,hh);
plot(ww,abs(HH))]]>
HH=freqz(hh,1,ww);
plot(ww,HH) ]]>
HH=freqz(hh,ww);
plot(ww,abs(HH))]]>
HH=freqz(hh,1,ww);
plot(ww,abs(HH))]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Which one of the following can display the MATLAB indices where the impulse response is equal to zero? ]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Which one of the following can display the DC value of the Frequency Reponse? ]]>
+You have a hard time limit for this on-Line Exercise. After the time expires, you will NOT BE ABLE TO SAVE ANY MORE ANSWERS.
+Whenever you complete an answer, hit the "Save Answer" button to update your answer in the WebCT record. +When you are finished with all the questions, hit the "FINISH" button.
+ +Check the button below to confirm that you understand these instructions +]]>
+ + +Check the button below to confirm that you understand these instructions +]]>
y = x * x;
+]]>
y = x * x;
+]]>
y = x .* x;
+]]>
x = x .* x;
+]]>
y = x .* x; +]]>
fs = 11025;
tt = (0:round(0.25*fs))/fs;
Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 5? And this is another way.]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
into another domain where signals can be representd by polynomials and systems can be
represented by rational functions. This transformation greatly simplifies signal manipulation
and filter design. ]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Assuming that the filter was designed via the Hamming-sinc formula, which one of the following can display the values of all the passband frequencies? The passband is defined as same as Bandpass Filters lab. ]]>
Which coefficient is equal to -1? ]]>
Since x[n] is a discrete-time sinusoid, its spectrum will contain an infinite number of lines in the omega-hat domain. Select the location of two of these omega-hat frequencies (in radians). + +]]>
Find H(ejω) where ω is the normalized frequency called "omega-hat" in the text.
]]>Each string row vector is an array of characters ('0' or '1') in MATLAB, e.g., '0010110101110'. + +
Which of the following is the correct way +to form the bit string sent out from modem? +]]>
Mark ALL the correct solutions. +]]>
HH=freqz(hh,1,ww);
plot(ww,abs(HH)) ]]>
HH=freqz(ww,hh);
plot(ww,abs(HH))]]>
HH=freqz(hh,1,ww);
plot(ww,HH) ]]>
HH=freqz(hh,ww);
plot(ww,abs(HH))]]>
HH=freqz(hh,1,ww);
plot(ww,abs(HH))]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Which one of the following can display the MATLAB indices where the impulse response is equal to zero? ]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Which one of the following can display the DC value of the Frequency Reponse? ]]>
+You have a hard time limit for this on-Line Exercise. After the time expires, you will NOT BE ABLE TO SAVE ANY MORE ANSWERS.
+Whenever you complete an answer, hit the "Save Answer" button to update your answer in the WebCT record. +When you are finished with all the questions, hit the "FINISH" button.
+ +Check the button below to confirm that you understand these instructions +]]>
+ + +Check the button below to confirm that you understand these instructions +]]>
y = x * x;
+]]>
y = x * x;
+]]>
y = x .* x;
+]]>
x = x .* x;
+]]>
y = x .* x; +]]>
for k=1:N
x(k) = k/10;
y(k) = exp(-j*pi*x(k));
end
plot(x,abs(y));You are asked to replace this block of code by another one that has NO for loop in it. Which of the following is the correct code to make the same plot? +]]>
y = exp(-j*pi*x);
plot(x, abs(y)); ]]>
y(k) = exp(-j*pi*(1:N)/10);
plot(k/10, abs(y));]]>
y = exp(-j*pi*(1:N)/10);
plot(x, abs(y)); ]]>
y = exp(-j*pi*(1:N)/10);
plot((1:N)/10, abs(y)); ]]>
(Note: there are 26 lectures; attendance means stayed for more than 45 minutes.) +]]>
if(xx<0), count=count+1, end
end]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
+If the FUNDAMENTAL period is defined to be To = 12, which of the following signals is synthesized (approximately) as N becomes large (>20)? +
NOTE: The Fourier Series coefficients for |k| < N are used in the synthesis. +]]>
+** TIME LIMIT ** +
+Here is the usual warning: You have a hard time limit for this on-Line Exercise. After the time expires, you will NOT BE ABLE TO SAVE ANY MORE ANSWERS.
+Whenever you complete an answer, hit the "Save Answer" button, and that will update the timer. Hit the "FINISH" button when you finish all the questions,
+ +Check the button below to confirm that you understand these instructions. +]]>
+If you wish to resize your quiz window when taking a quiz using a Netscape web browser, you MUST resize it and then press "CTRL-R" to reload the screen BEFORE you enter any answers.
+ + +Check the button below to confirm that you understand these instructions +]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Which one of the following can display the length of the impulse response? ]]>
Each string row vector is an array of characters ('0' or '1') in MATLAB, e.g., '0010110101110'. + +
Which of the following is the correct way +to form the bit string sent out from modem? +]]>
+describe the type of filter in terms of its frequency response. +]]>
+SS = struct('A',7,'f',440,'fs',8000,'dur',2);
+
+Assume the standard interpretation for the parameter names of the sinusoid. +]]>
xx(4:6)]]>
+function prelab = funny(waw) +
prelab = waw.*(waw>=0 & waw<2) + (waw.^2).*(waw>=3 & waw<=5) + 4*waw.*(waw>=6 & waw<=10); + +
+]]>
+f(t) = +
t, when (0<= t <2) +
t^2 when (3<= t <=5) +
4*t when (6<= t <=10) +
zero, otherwise + +
+which of the following codes DOES NOT compute correctly the integral of the function defined above over the period [2, 5] using quad8() and inline()? +]]>
+If the FUNDAMENTAL period is defined to be To = 12, which of the following signals is synthesized (approximately) as N becomes large (>20)? +
NOTE: The Fourier Series coefficients for |k| < N are used in the synthesis. +]]>
nn = 0:10000; +xx = 11*sin(2*pi*0.2*nn);Which one of the following will correctly play the sound? ]]>
+You have a hard time limit for this on-Line Exercise. After the time expires, you will NOT BE ABLE TO SAVE ANY MORE ANSWERS.
+Whenever you complete an answer, hit the +"Save Answer" button to update your answer in the WebCT record. +When you are finished with all the questions, hit the "FINISH" button.
+ +You can have MATLAB running while you answer these questions.
+This is an open book and open notes test. But, it must be your own work. You are NOT allowed to discuss it with anyone else while answering these questions.
+ + +Check the button below to confirm that you understand these instructions +]]>
Each string row vector is an array of characters ('0' or '1') in MATLAB, e.g., '0010110101110'. + +
Which of the following is the correct way +to form the bit string sent out from modem? +]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Assuming that the filter was designed via the Hamming-sinc formula, which one of the following can display the values of all the stopband frequencies? The stopband is defined as same as Bandpass Filters lab. ]]>
xx = cos(2*pi*tt*(800+df)) + cos(2*pi*tt*(800-df));
plot(tt,xx) +
Determine the value of df.
]]>+* Start the quiz at the beginning of your lab time (within the first 10 minutes) +
* Do the online quiz in the lab room (BH-216) with a TA proctoring. +
+* The real Pre/Post Lab quiz is open book, open notes, and open MATLAB. +
+* Obey the GT Honor Code: do NOT discuss the questions with anyone else during the lab time.
+* Furthermore, since the on-line questions are used throughout the week in other sections, do not tell students in other sections about the contents.
+ +The score of this practice quiz will NOT count into your final grade. +
+Check the button below to confirm that you understand these instructions +]]>
At the end of these commands, what is the variable ans equal to? ]]>
+ +There seems to be a software/hardware limitation with the BH-216 lab machines. You should run only one Web browser and one instance of MATLAB while taking the PreLab quiz, and NO other applications. Using other applications during the PreLab will be at YOUR OWN RISK. + +
+There have been random reports that opening PDF files while taking a WebCT quiz might slow down or freeze Windows on these computers. If you expect to use lecture notes or any PDF file during the quiz, the safest way is to have a hard copy of them printed before coming to lab.
+ +
Check the button below to confirm that you understand these instructions. +]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Which one of the following can display the length of the impulse response? ]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Which one of the following can display the values of all the stopband frequencies? The stopband is defined as same as Bandpass Filters lab. ]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); ++ +Which one of the following can display the values of all the passband frequencies? The passband is defined as same as Bandpass Filters lab. +]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Which one of the following can display the length of the impulse response? ]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Which one of the following can display the values of all the stopband frequencies? The stopband is defined as same as Bandpass Filters lab. ]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Which one of the following can display the MATLAB indices where the impulse response is equal to zero? ]]>
ww = pi*(-1000:1000)/1000; +HH = freqz(bb,1,ww); +Which one of the following can display the DC value of the Frequency Reponse? ]]>
f = 10000; % Hz]]>
fs = 32000; % Hz
tt = 0:(1/fs):3;
xx = cos(2*pi*f*tt);
soundsc(xx,fs)
+describe the type of filter in terms of its frequency response. +]]>
Which of the following commands will properly display the image of Buzz? Pick ONE. +]]>
sumx = xx(1:length(xx)); ++]]>
sumx = xx * transpose(xx); ++]]>
sumx = xx * transpose(ones(1,length(xx))); ++]]>
sumx = transpose(xx) * ones(1,length(xx)); ++]]>
x1 = cos(2*pi*400*t + 35*cos(2*pi*10*t)) ++Which of the following most accurately describes the shape of the spectrogram +of the modulated signal? +
NOTE: like the AM Lab Warm-up, the spectrogram will exhibit sinusoidal shapes. +
+(Assume a sampling rate of 44.1kHz, and a spectrogram display that only shows positive frequencies) + +]]>
I intend/desire to remain in Georgia after graduation from Georgia Tech. +]]>
yy = signal(t1,t2) +times = t1:1/10000:t2; +yy = cos(2*pi*times); ++]]>
function yy = signal(t1,t2) +times = t1:1/10000:t2; +yy = cos(2*pi*times); ++]]>
mfile yy = signal(t1,t2) +times = t1:1/10000:t2; +yy = cos(2*pi*times); ++]]>
function yy = signal(times) +times = t1:1/10000:t2; +yy = cos(2*pi*times); ++]]>
function xx = signal(t1,t2) +times = 3:1/10000:7; +yy = cos(2*pi*times); ++]]>
nn = 0:10000; +xx = 15*sin(2*pi*0.1*nn);+Which one of the following will correctly play the sound? +]]>
+NOTE: In general, if the fundamental frequency is 10Hz then 30Hz is the 3rd harmonic. +]]>
+NOTE: In general, if the fundamental frequency is 10Hz then 30Hz is the 3rd harmonic. +]]>
What happens to the impulse response and the frequency response +]]>
plot(ww,angle(bb));
+]]>
H=freqz(bb,1,ww);
plot(ww,imag(H));
+]]>
H=freqz(bb,1,ww);
plot(ww,angle(H));
+]]>
H=freqz(ww,1,bb);
plot(ww,angle(H));
+]]>
plot(ww,bb);
+]]>
H=freqz(bb,1,ww);
plot(ww,abs(H));
+]]>
H=freqz(bb,1,ww);
plot(ww,H);
+ +]]>
+(Repeated here for convenience: technology that will support in class note taking, connect those notes with the online lecture material, and also connect those notes with other resources available for the course) +]]>
+which of the following codes DOES NOT plot correctly the above function over the period [0, 10] using fplot() and inline()? + +]]>
+f(t) = +
2*t, when (0<= t <2) +
t-5 when (3<= t <=5) +
exp(0.4*t) when (6<= t <=10) +
zero, otherwise + +
+which of the following codes plots correctly the function defined above over the period [0, 10] using fplot() and inline()? +
There might be 2 correct answers. Choose any one. +]]>
+LPFs Passband edge of 0.7*pi means, the passband extends from the frequency -0.7*pi to +0.7*pi. +]]>
+LPFs Passband edge of 0.6*pi means, the passband extends from the frequency -0.6*pi to +0.6*pi. +]]>
function PreLab10 = mycos(t)
+%MYCOS defines a cosine
+%
+PreLab10 = cos(pi*t);
+Which command will correctly plot one period of the cosine? ]]>
+You have a deadline for this on-Line Exercise. After the time expires, you will NOT BE ABLE TO SAVE ANY MORE ANSWERS.
+Thus, hit the "Save Answer" button often. +That will also update the timer. +
Check the button below to confirm that you understand these instructions. +]]>
xx = cos(2*pi*250*tt+pi/3); ]]>
+HPFs Passband edge of 0.7*pi means, the passband extends from the frequency -0.7*pi to -pi and 0.7*pi to pi +]]>
+HPFs Passband edge of 0.9*pi means, the passband extends from the frequency -0.9*pi to -pi and 0.9*pi to pi +]]>
+HPFs Passband edge of 0.8*pi means, the passband extends from the frequency -0.8*pi to -pi and 0.8*pi to pi +]]>
+fs = 1850; ++Which of the following pair of frequencies will be seen in a spectrogram for +the DTMF signal generated by telephone key number 2? +]]>
+fs = 1850; ++Which of the following pair of frequencies will be seen in a spectrogram for +the DTMF signal generated by telephone key number 1? +]]>
stem(yy(nn),nn) +]]>
stem(nn,yy(nn)) +]]>
stem(nn,yy(nn)) +]]>
stem(nn,yy(nn+1)) +]]>
+fs = 1850; ++Which of the following pair of frequencies will be seen in a spectrogram for +the DTMF signal generated by telephone key number 3? +]]>
+ A = [ a+b*j , c+d*j ] ++Assume that the parameters a, b, c, and d would have numerical values. +]]>
function [xx, times] = signal(tstart,tend) +times = tstart:1/100:tend; +xx = []; +for ii=1:length(times) + xx = [xx, cos(2*pi*times(ii))]; +end; ++ +What is the correct way to call this function and make a plot of the sinusoid over the interval from t=1 to t=2 ? +]]>
+yy = signal(1,2); plot(times,yy) ++]]>
+[yy,tt] = synsig([1,2]); plot(tt,yy) ++]]>
+[yy,tt] = signal(1,2); plot(tt,yy) ++]]>
+[yy,tt] = synsig(1,2); plot(tt,yy) ++]]>
+plot( 1:2, synsig(1,2) ) ++]]>
+fs = 1850; ++Which of the following pair of frequencies will be seen in a spectrogram for +the DTMF signal generated by telephone key number 4? +]]>
+fs = 1850; ++Which of the following pair of frequencies will be seen in a spectrogram for +the DTMF signal generated by telephone key number 5? +]]>
+fs = 1850; ++Which of the following pair of frequencies will be seen in a spectrogram for +the DTMF signal generated by telephone key number 6? +]]>
+If the FUNDAMENTAL period is defined to be To = 12, which of the following signals is synthesized (approximately) as N becomes large (>20)? +
NOTE: The Fourier Series coefficients for |k| < N are used in the synthesis. +]]>
+fs = 1850; ++Which of the following pair of frequencies will be seen in a spectrogram for +the DTMF signal generated by telephone key number 7? +]]>
nn = (0:round(0.25*fs));Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 9? ]]>
+fs = 1850; ++Which of the following pair of frequencies will be seen in a spectrogram for +the DTMF signal generated by telephone key number 8? +]]>
+fs = 1850; ++Which of the following pair of frequencies will be seen in a spectrogram for +the DTMF signal generated by telephone key number 9? +]]>
+If not, Please complete it now. +]]>
xx = cos(w*t + phi);]]>
function PreLab10 = fcos(t)
+% FCOS defines a cosine
+%
+PreLab10 = cos(pi*t);
+Which command will correctly plot one period of the cosine? ]]>
angle(z1) + angle(z2) ++]]>
real(z1*z2) + j*imag(z1*z2) ++]]>
phase(z1+z2) ++]]>
angle(z1) * angle(z2) ++]]>
atan( imag(z1*z2)/real(z1*z2) ) ++]]>
+ +You have a time limit for this on-Line Exercise.
+Whenever you complete an answer, hit the "Save Answer" button to update your answer in the WebCT record.
+When you are finished with all the questions, hit the "FINISH" button.
+ + +Check the button below to confirm that you understand these instructions. +]]>
You are asked to replace this block of code by another one that contains ONE for loop. Which of the following is the correct code to make the same plot? ]]>
If the FUNDAMENTAL period is defined to be To = 2, which of the following signals is synthesized (approximately) as N becomes large (>20)?
NOTE: The Fourier Series coefficients for |k| < N are used in the synthesis. ]]>
hh = (2/32)*cos(0.75*pi*[0:31]); +ww = 0.1*pi*(0:0.0001:10); +HH = freqz(hh,1,ww); +Find both the center frequency wc for this BPF and its passband width.
The passband width is defined as the length of the frequency region where the magnitude of the frequency response is greater than 0.707. ]]>
passband width = 0.1738 + +]]>
passband width = 0.1738 + +]]>
passband width = 2/32 + +]]>
passband width = 0.0869 + +]]>
passband width = 0.0869 + +]]>
function [xx, times] = signal(tend) +times = tend(1):1/100:tend(2); +xx = []; +for ii=1:length(times) + xx = [xx, cos(2*pi*times(ii))]; +end; +What is the correct way to call this function and make a plot of the sinusoid over the interval from t=1 to t=2 ? ]]>
+If not, go to + +https://gtwebapps.gatech.edu/cfprod/cios_new/student_login.cfm and look for ECE2025A. +]]>
Assume the length of xx is greater than 100. +]]>
You are asked to replace this block of code by another one that contains ONE for loop. Which of the following is the correct code to make the same plot? ]]>
You are asked to replace this block of code by another one that contains ONE for loop. Which of the following is the correct code to make the same plot? ]]>
nn = N/2:N-1? +]]>
+NOTE: PeZ will put a second pole at the conjugate location, which corresponds to negative frequency. + +]]>
function PreLab10 = fcos(t)
+% Defines a cosine
+%
+PreLab10 = cos(pi*t);Which command will correctly plot one period of the cosine? ]]>+If not, go to + +https://gtwebapps.gatech.edu/cfprod/cios_new/student_login.cfm and look for ECE2025Lnn, where Lnn is your Lab section number +]]>
+You have a DEADLINE for this on-Line Exercise. + +
After the time expires, you will NOT BE ABLE TO SAVE ANY MORE ANSWERS.
+Hit the "Save Answer" button often. +
+
Check the button below to confirm that you understand these instructions. +]]>
+of L = 101. The filter coefficients are stored in the vector bb. +
+Given a signal: +
+xx = cos(2*pi*100*tt) + sin(2*pi*200*tt) + cos(2*pi*300*tt); +
+where tt=-4000:1/10000:4000;
+ +Which commands could be used to pass only the sine and reject the two cosines by +using a bandpass filter? +Note: the BPF would be created from the LPF. +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = conv(hh,xx); +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+yy = xx.*hh.*cos(2*pi*200*((0:100)-50)) +]]>
+yy = conv(bb2,xx) +]]>
+yy = bb2.*xx +]]>
+yy = conv(bb2,xx) +]]>
+Check the box below to indicate you have read these rules. +]]>
3 7 11 15 19 23+]]>
In general, what can be said about the placement of the poles to guarantee stability?
+If necessary, use PeZ to generate examples with multiple poles +]]>
C:\\appl\\matlab\\bin. while in an ECE computer lab. +]]>
hh = (2/64)*cos(1.6965*[0:63]); +ww = 0.1*pi*(0:0.0001:10); +HH = freqz(hh,1,ww); ++Find both the center frequency wc for this BPF, and its passband width. +
The passband width is defined as the length of the frequency region where the magnitude of the frequency response is greater than 0.707. +]]>
passband width = 0.0435 + +]]>
passband width = 0.0435 + +]]>
passband width = 2/64 +]]>
passband width = 0.0874 + +]]>
passband width = 0.0874 + +]]>
(Answer given in integer format) +]]>
+]]>
xx = cos(2*pi*3*tt);
+]]>
xx = cos(2*pi*11025*tt);
+]]>
xx = cos(2*pi*3000*tt);
+]]>
xx = cos(2*pi*3000*tt);
+]]>
+If not, go to that link under the "On-Line Quizzes and Surveys" in Web-CT.
+These questions are tailored to ECE-2025, so the +answers will be more useful to us than the general ones in the required GT surveys. +
+Note: the answer below counts 10 pts on Lab Quiz #4. + +]]>
function PreLab10 = fcos(t)
+% Defines a cosine
+%
+PreLab10 = cos(pi*t);
+Which command will correctly calculate the integral of one period of the cosine? ]]>
Each string row vector is an array of characters ('0' or '1') in MATLAB, e.g., '0010110101110'. + +
Which of the following is the correct way +to form the bit string sent out from modem? +]]>
Each string row vector is an array of characters ('0' or '1') in MATLAB, e.g., '0010110101110'. + +
Which of the following is the correct way +to form the bit string sent out from modem? +]]>
f = 32; %--kHz+ + + + +]]>
fs = 10; %--kHz
tt = 0:(1/fs):3;
xx = cos(2*pi*f*tt);
x1 = cos(2π 700 t + 30 cos(2π 10 t))+Which of the following most accurately describes the shape of the spectrogram +of the modulated signal? +
NOTE: like the AM Lab Warm-up, the spectrogram will exhibit sinusoidal shapes. +
+(Assume a sampling rate of 44.1kHz, and a spectrogram display that only shows positive frequencies) + + + +]]>
x(t) = cos(ωt + φ);]]>
of 25 Hz, a stopband cutoff frequency of 50 Hz and a filter length
+of L = 101. The filter coefficients are stored in the vector bb. +
+Given a signal: +
+xx = cos(2*pi*100*tt) + sin(2*pi*200*tt) + cos(2*pi*300*tt); +
+where tt=-4000:1/10000:4000;
+ +Which commands could be used to pass only the sine and reject the two cosines by +using a bandpass filter? +Note: the BPF would be created from the LPF. +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = conv(hh,xx); +]]>
+yy = conv(bb2,xx) +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = conv(hh,xx); +]]>
+yy = conv(bb2,xx) +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = conv(hh,xx); +]]>
+yy = conv(bb2,xx) +]]>
% Returns a single sinusoid with the key and duration specified
fs = 11025;
tt = 0:1/fs:dur;
f0 = 440*2^((keynum-49)/12);
tone = cos(2*pi*f0*tt); +
A student wants to modify the function so that the tone created by this function has THREE frequency components. The new tone should be the sum of three sinusoids, one of which is the fundamental, f0, and the other two which are of frequencies 2 and 3 times higher than the fundamental respectively. The amplitudes (and phases) can be the same. Which one of the following is a correct modification that will accomplish this task?
+ + + +]]>tone = cos(2*pi*(2*f0+3*f0)*tt); +]]>
tone = cos(2*pi*f0*tt) + cos(2*pi*2*f0*tt) + cos(2*pi*3*f0*tt) +]]>
tone = cos(2*pi*f0*([1 2 3]')*tt); +]]>
f0 = f0 + 2*f0 + 3*f0; +]]>
What is the correct way to add yy to the MIDDLE ten points of xx?
The result (called zz) should be 30 points long.
Assume all vectors are row vectors.
Do not assume that zz has been initialized. +]]>
+of L = 101. The filter coefficients are stored in the vector bb. +
+Given a signal: +
+xx = sin(2*pi*100*tt) + cos(2*pi*200*tt) + cos(2*pi*300*tt); +
+where tt=-4000:1/10000:4000;
+ +Which commands could be used to pass only the sine and reject the two cosines by +using a bandpass filter? +Note: the BPF would be created from the LPF. +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = conv(hh,xx); +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+yy = conv(bb2,xx) +]]>
+yy = hh.*cos(2*pi*100*((0:100)-50)) +]]>
+yy = bb2.*xx +]]>
+yy = conv(bb2,xx) +]]>
+Two for Georgia Tech: one for Lecture and one for Recitation. These can be found at +
+http://www.coursesurvey.gatech.edu +
Use your banner id +and banner pin to fill out a survey for each of your courses. +
+One in Web-CT. Look for the "Course Survey" under the on-line Quizzes link. + +]]>
You construct a sinusoidal signal xx=cos(2*pi*100*tt); +
You want to know an estimate of the value of the signal (xx) at the time 1.6 seconds . Which of the following MATLAB statements will do that for you (without errors or warnings)? +]]>
There is only one correct answer. ]]>
function [xx, times] = signal(tend) +times = tend(1):1/100:tend(2); +xx = []; +for ii=1:length(times) + xx = [xx, cos(2*pi*times(ii))]; +end; ++ +What is the correct way to call this function and make a plot of the sinusoid over the interval from t=1 to t=2? + +]]>
+yy = signal(1,2); plot(times,yy) ++]]>
+[yy,tt] = synsig([1,2]); plot(tt,yy) ++]]>
+[yy,tt] = signal(1,2); plot(tt,yy) ++]]>
+[yy,tt] = synsig(1,2); plot(tt,yy) ++]]>
+plot( 1:2, synsig(1,2) ) ++]]>
+M = 50; nn = 0:M; +LW = sin(2*pi/M*(nn-M/2))./(2*pi/M*(nn-M/2)); %-- Lanczos window +LW(M/2 + 1) = 1; %-- fix divide by zero +wc = 0.3*pi; +sincwc = sin(wc*(nn-M/2))./(pi*(nn-M/2)); %-- sinc function +sincwc(M/2 + 1) = wc/pi; %-- fix divide by zero +bb = sincwc.*LW; %-- Filter Coefficients ++ +Choose all correct answers from the following choices, which will evaluate the frequency response of the filter at frequency 0. +]]>
+M = 50; nn = 0:M; +LW = sin(2*pi/M*(nn-M/2))./(2*pi/M*(nn-M/2)); %-- Lanczos window +LW(M/2 + 1) = 1; %-- fix divide by zero +wc = 0.3*pi; +sincwc = sin(wc*(nn-M/2))./(pi*(nn-M/2)); %-- sinc function +sincwc(M/2 + 1) = wc/pi; %-- fix divide by zero +bb = sincwc.*LW; %-- Filter Coefficients ++ +Choose all correct answers from the following choices, which will evaluate the frequency response of the filter at frequency 0. +]]>
+M = 50; nn = 0:M; +LW = sin(2*pi/M*(nn-M/2))./(2*pi/M*(nn-M/2)); %-- Lanczos window +LW(M/2 + 1) = 1; %-- fix divide by zero +wc = 0.3*pi; +sincwc = sin(wc*(nn-M/2))./(pi*(nn-M/2)); %-- sinc function +sincwc(M/2 + 1) = wc/pi; %-- fix divide by zero +bb = sincwc.*LW; %-- Filter Coefficients ++ +Choose all correct answers from the following choices, which will evaluate the frequency response of the filter at frequency equal to 'pi'. +]]>
size(V) ==> 1 100 +
+
Which of the following statements will generate an error? +
+
Mark all possible solutions. +]]>
xx = cos(2*pi*2000*tt);Which of the following lines will correctly play the sound? ]]>
function PreLab10 = fcos(t)
+% Defines a cosine
+%
+PreLab10 = cos(pi*t);
+Which command will correctly calculate the integral of one period of the cosine? ]]>hh = (2/16)*cos(0.25*pi*[0:15]); +ww = 0.1*pi*(0:0.0001:10); +HH = freqz(hh,1,ww); ++Find both the center frequency wc for this BPF, and its passband width. +
The passband width is defined as the length of the frequency region where the magnitude of the frequency response is greater than 0.707. +]]>
passband width = 0.3466 + +]]>
passband width = 0.1733 + +]]>
passband width = 0.3466 + +]]>
passband width = 0.1733 + +]]>
passband width = 0.1733*2*pi + +]]>
of 25 Hz, a stopband cutoff frequency of 50 Hz and a filter length
+of L = 101. The filter coefficients are stored in the vector bb. +
+Given a signal: +
+xx = cos(2*pi*100*tt) + cos(2*pi*200*tt) + sin(2*pi*300*tt); +
+where tt=-4000:1/10000:4000;
+ +Which commands could be used to pass only the sine and reject the two cosines by +using a bandpass filter? +Note: the BPF would be created from the LPF. +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = conv(hh,xx); +]]>
+yy = conv(bb2,xx) +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = conv(hh,xx); +]]>
+yy = conv(bb2,xx) +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = conv(hh,xx); +]]>
+yy = conv(bb2,xx) +]]>
tt = 0:1/8000:2; +xx = cos(2pi*tt); +yy = xx+3; +plot(tt,yy) +When it is run, the following error is reported.
??? xx=cos(2 | Missing operator, comma, or semi-colon. +Error in ==> h:\test.m +On line 2 ==> xx=cos(2pi*tt); +Which line contains the error? ]]>
This goal has been accomplished by me. +]]>
+ +Check the box below to indicate you have read these rules. +]]>
function tone = note(keynum,dur)A student wants to modify the function so that the tone created by this function has TWO frequency components. The new tone should be the sum of two sinusoids, one of which is the frequency for the key number, and the other of which has a frequency 1.5 times higher. The amplitudes (and phases) can be the same. Which one of the following is a correct modification that will accomplish this task? + +]]>
% Returns a single sinusoid with the key and duration specified
fs = 11025;
tt = 0:1/fs:dur;
f0 = 440*2^((keynum-49)/12);
tone = cos(2*pi*f0*tt);
tone = cos(2*pi*(3/2)*f0*tt); +]]>
tone = cos(2*pi*f0*([1 3/2]')*tt); +]]>
tone = cos(2*pi*f0*tt) + cos(2*pi*3/2*f0*tt) +]]>
f0 = f0 + 3/2*f0; +]]>
+You may cut ("CTRL-C") and paste ("CTRL-V") lines from the WebCT quiz window to the MATLAB window to speed up your problem solving.
+For example, cut a MATLAB statement from WebCT, and paste it into the MATLAB command window in order to execute it.
+ +Check the button below to confirm that you understand this tip. +]]>
+Note: this operation is called "CONCATENATION." +]]>
sig = [xx, zeros(1, silence), yy]; +]]>
+NOTE: fix(N/4) takes the integer part if N is not evenly divisible by 4. +]]>
+If the FUNDAMENTAL period is defined to be To = 5, which of the following signals is synthesized (approximately) as N becomes large (>20)? +
NOTE: The Fourier Series coefficients for |k| < N are used in the synthesis. +]]>
nn = (0:round(0.25*fs));Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 1? ]]>
tt = 0:1/8000:1.0; +xx1 = cos(2*pi*440*tt); +xx2 = cos(2*pi*360*tt); +We want to create a new vector called zz that when played though the speaker with soundsc(zz,8000) will be two sequential tones with the FIRST tone being HIGHER in frequency.
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: ]]>
function [xx, times] = signal(tstart,tend) +times = tstart:1/100:tend; +xx = []; +for ii=1:length(times) + xx = [xx, cos(2*pi*times(ii))]; +end; ++ +What is the correct way to call this function and make a plot of the sinusoid over the interval from t=1 to t=2 ? + +]]>
+signal(1,2); plot(xx, times) ++]]>
+signal(1,2); plot(times, xx) ++]]>
+yy = signal(1,2); plot(times,yy) ++]]>
+[yy,tt] = signal([1,2]); plot(tt,yy) ++]]>
+[yy,tt] = signal(1,2); plot(tt,yy) ++]]>
+plot( 1:2, signal(1,2) ) ++]]>
+[tt,yy] = signal(1,2); plot(tt,yy) ++]]>
Ψ(t) = 2πμt2 + 2πf0t + φas: ]]>
+Running the MATLAB code in the next problem(s) will lock up your computer. + +
+For such questions you should ANALYZE the code, not "cut and paste" the whole thing to run it.
+
+As usual, Hit the "Save Answer" button often, and when you are finished with all the questions, hit the "FINISH" button.
+ +
Check the button below to confirm that you understand these instructions. +]]>
Each string row vector is an array of characters ('0' or '1') in MATLAB, e.g., '0010110101110'. + +
Which of the following is the correct way +to form the bit string sent out from modem? +]]>
+SS = struct('strings',{{'hello','yes'}},'lengths',[5 3])
+
+]]>+
+bb = ones(1,4)/2; +ww = [-pi:2*pi/99741000:pi] +HH = exp(-j*1.5*ww).*(cos(0.5*ww)+cos(1.5*ww)); +plot(ww,abs(HH)); ++ +Which of the following code fragments gives the same plot as the one produced by the above code? +
(Don't try to run this code, just analyze it.) +]]>
H = freqz(bb,1,ww) +
plot(ww,abs(bb)); +]]>
H = freqz(bb,HH,ww) +
plot(ww,abs(H)); +]]>
H = freqz(HH,1,ww) +
plot(ww,abs(H)); +]]>
H = freqz(bb,1,ww) +
plot(ww,H); +]]>
H = freqz(bb,1,ww) +
plot(ww,abs(H)); +]]>
H = freqz(ww,1,bb) +
plot(ww,abs(H)); +]]>
H = freqz(HH,bb,ww) +
plot(ww,abs(H)); +]]>
+]]>
fs = 11025; +tt = (0:round(0.25*fs))/fs;
+Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 2? + +]]>
fs = 11025; +tt = (0:round(0.25*fs))/fs;+
+Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 3? + +]]>
fs = 11025; +tt = (0:round(0.25*fs))/fs;+
+Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number A? +]]>
fs = 11025; +nn = (0:round(0.25*fs));+Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 4? + +]]>
fs = 11025; +nn = (0:round(0.25*fs));+Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 7? +]]>
fs = 11025; +nn = (0:round(0.25*fs));+Which MATLAB code would you use to generate the appropriate DTMF signal to represent telephone key number 8? + +]]>
In other words, the vectors need to be "concatenated." Which of the following pieces of MATLAB code will do this: +]]>
plot(ww,abs(bb));
+]]>
H=freqz(bb,1,ww);
plot(ww,real(H));
+]]>
H=freqz(ww,1,bb);
plot(ww,abs(H));
+]]>
H=freqz(bb,1,ww);
plot(ww,abs(H));
+]]>
H=freqz(bb,1,ww);
plot(ww,H);
+]]>
H=freqz(bb,1,ww);
plot(ww,angle(H));
+]]>
H=freqz(bb,1,ww);
plot(ww,mag(H));
+ + +]]>
Which of the following commands will properly display the image of the Tech Tower? Pick ONE. +]]>
+ +H(jω) = 3/(jω + 2) + +
+ +Signal y1(t) is output of the system with input signal
+ +x1(t) = 5 + 3 cos( 30 π t) + +
+ +Similarly, signal y2(t) is output of the system with input signal
+ +x2(t) = 5 + 3 cos( 70 π t) + +
+ + +Choose correct answer(s) from the following (it could be multiple answers) +]]>
+ +H(jω) = 6jω/(jω + 7) + +
+ +Signal y1(t) is output of the system with input signal
+ +x1(t) = 3 + 8 cos( 30 π t) + +
+ +Similarly, signal y2(t) is output of the system with input signal
+ +x2(t) = 3 + 8 cos( 80 π t) + +
+ + +Choose correct answer(s) from the following (it could be multiple answers) +]]>
res = 0; res = res + xx(:); ++]]>
res = ones(1,100) * xx'; ++]]>
res = xx(1:100); ++]]>
res = xx * ones(100,1); ++]]>
+Check the button below to confirm that you understand these instructions +]]>
+Check the button below to confirm that you understand these instructions +]]>
+At the end of these commands, what is the variable ans equal to? +]]>
aa = 5 + 5i; + bb = 3 + 3i; + cc = 7 + 7i; ++ +Which of the following commands can construct a row vector with 3+3i as the first element, 5+5i as the second element, and 7+7i as the last element? +]]>
+function [xxx, times] = makesig(ttt) +times = ttt(1):1/100:ttt(2); +xxx = real( exp( 2i*pi*times ) ); ++ +What is the correct way to call this function and make a plot of the signal for t from 0 to 10 in a subplot frame? +]]>
+yy = mysig(0,10); subplot(2,1,1), plot(times,yy) ++]]>
+[yy,tt] = mysig([0,10]); subplot(2,1,1), plot(tt,yy) ++]]>
+[yy,tt] = makesig(0,10); plot(tt,yy), subplot(2,1,1) ++]]>
+[yy,tt] = makesig([0,10]); plot(tt,yy), subplot(2,1,1) ++]]>
+plot( 0:10, mysig([0,10]) ), subplot(2,1,1) ++]]>
angle(z1) - angle(z2) ++]]>
angle( z1 * conj(z2) ) ++]]>
angle(z1 - z2) ++]]>
angle(z1/z2) ++]]>
angle( z1 * z2' ) ++]]>
of 25 Hz, a stopband cutoff frequency of 50 Hz and a filter length
+of L = 101. The filter coefficients are stored in the vector bb. +
+Given a signal: +
+xx = sin(2*pi*100*tt) + cos(2*pi*200*tt) + cos(2*pi*300*tt); +
+where tt=-4000:1/10000:4000;
+ +Which commands could be used to pass only the sine and reject the two cosines by +using a bandpass filter? +Note: the BPF would be created from the LPF. +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = conv(hh,xx); +]]>
+yy = conv(bb2,xx) +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = conv(hh,xx); +]]>
+yy = conv(bb2,xx) +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = conv(hh,xx); +]]>
+yy = conv(bb2,xx) +]]>
Since x[n] is a discrete-time sinusoid, its spectrum will contain an infinite number of lines in the omega-hat domain. Select the location of two of these omega-hat frequencies (in radians). + +]]>
function [xx, times] = synsig(tstart,tend) +times = tstart:1/100:tend; +xx = []; +for ii=1:length(times) + xx = [xx, cos(2*pi*times(ii))]; +end; ++ +What is the correct way to call this function and make a plot of the sinusoid over the interval from t=1 to t=2 ? +]]>
+yy = signal(1,2); plot(times,yy) ++]]>
+[yy,tt] = signal([1,2]); plot(tt,yy) ++]]>
+[yy,tt] = signal(1,2); plot(tt,yy) ++]]>
+[yy,tt] = synsig(1,2); plot(tt,yy) ++]]>
+plot( 1:2, synsig(1,2) ) ++]]>
How does this affect the impulse response h[n], and frequency response? +]]>
+You have a hard time limit for this on-Line Exercise. After the time expires, you will NOT BE ABLE TO SAVE ANY MORE ANSWERS.
+Whenever you complete an answer, hit the "Save Answer" button, and that will update the timer. +When you are finished with all the questions, hit the "FINISH" button.
+ +You can have MATLAB running while you answer these questions.
+ +Check the button below to confirm that you understand these instructions. +]]>
+x1 = cos(2*pi*500*t + 25*cos(2*pi*10*t)) ++Which of the following most accurately describes the shape of the spectrogram +of the modulated signal? +
NOTE: like the AM Lab Warm-up, the spectrogram will exhibit sinusoidal shapes. +
+(Assume a sampling rate of 44.1kHz, and a spectrogram display that only shows positive frequencies) + +]]>
The tt vector is defined via:
tt = 0:(1/fs):2;Assume that the sampling frequency (fs) is very high. Which one of the following signals could have been used to generate the linear sweep in instantaneous frequency? ]]>
x1 = cos(2*pi*1000*t + 50*cos(2*pi*10*t))Which of the following most accurately describes the shape of the spectrogram of the modulated signal?
NOTE: The spectrogram will exhibit sinusoidal shapes.
(Assume a sampling rate of 44.1kHz, and a spectrogram display that only shows positive frequencies) ]]>
Which of the following commands will properly display the image of the shaft? Pick ONE. +]]>
x(t) = cos(ωt + φ)]]>
Since x[n] is a discrete-time sinusoid, its spectrum will contain an infinite number of lines in the omega-hat domain. Select the location of two of these omega-hat frequencies (in radians). + +]]>
+Suppose that the two roots from a second-degree polynomial B(z) are complex and they are also complex conjugates of one another. What can be said about the values of the polynomial coefficients b1 and b2 ? +
HINT: Try help roots in MATLAB; generate numerical examples to test your answer. +]]>
function [xx, times] = synsig(tend) +times = tend(1):1/100:tend(2); +xx = []; +for ii=1:length(times) + xx = [xx, cos(2*pi*times(ii))]; +end; ++ +What is the correct way to call this function and make a plot of the sinusoid over the interval from t=1 to t=2 ? +]]>
+yy = signal(1,2); plot(times,yy) ++]]>
+[yy,tt] = signal([1,2]); plot(tt,yy) ++]]>
+[yy,tt] = signal(1,2); plot(tt,yy) ++]]>
+[yy,tt] = synsig([1,2]); plot(tt,yy) ++]]>
+plot( 1:2, synsig(1,2) ) ++]]>
Which of the following MATLAB commands will produce a plot of xx versus tt (where tt is in seconds)? ]]>
+M = 50; nn = 0:M; +alpha = 2; +GW = exp(-0.5*( ((alpha*(nn-M/2))/(M/2)).^2 )); %-- Gaussian window +wc = 0.3*pi; +sincwc = sin(wc*(nn-M/2))./(pi*(nn-M/2)); %-- sinc function +sincwc(M/2 + 1) = wc/pi; %-- fix divide by zero +bb = sincwc.*GW; %-- Filter Coefficients ++ +Choose all correct answers from the following choices, which will evaluate the frequency response of the filter at frequency 0. +]]>
+M = 50; nn = 0:M; +alpha = 2; +GW = exp(-0.5*( ((alpha*(nn-M/2))/(M/2)).^2 )); %-- Gaussian window +wc = 0.3*pi; +sincwc = sin(wc*(nn-M/2))./(pi*(nn-M/2)); %-- sinc function +sincwc(M/2 + 1) = wc/pi; %-- fix divide by zero +bb = sincwc.*GW; %-- Filter Coefficients ++ +Choose all correct answers from the following choices, which will evaluate the frequency response of the filter at frequency 'pi' . +]]>
+ bb = ones(1,21)/21; +
+ +Mark all the choices (given below) that describe the output image: +]]>
+You have a DEADLINE for this on-Line Exercise. + +
After the time expires, you will NOT BE ABLE TO SAVE ANY MORE ANSWERS.
+Hit the "Save Answer" button often. +
+ +When you are finished with all the questions, hit the "FINISH" button.
+ +
Check the button below to confirm that you understand these instructions. +]]>
+ bb = [1 -1]; +
+ +Mark all the choices (given below) that describe the output image: +]]>
+ bb = ones(21,1)/21; +
+ +Mark all the choices (given below) that describe the output image: +]]>
+ bb = [1; -1]; +
+ +Mark all the choices (given below) that describe the output image: +]]>
Each string row vector is an array of characters ('0' or '1') in MATLAB, e.g., '0010110101110'. + +
Which of the following is the correct way +to form the bit string sent out from modem? +]]>
+M = 50; nn = 0:M; +alpha = 2; +GW = exp(-0.5*( ((alpha*(nn-M/2))/(M/2)).^2 )); %-- Gaussian window +wc = 0.3*pi; +sincwc = sin(wc*(nn-M/2))./(pi*(nn-M/2)); %-- sinc function +sincwc(M/2 + 1) = wc/pi; %-- fix divide by zero +bb = sincwc.*GW; %-- Filter Coefficients ++ +Choose all correct answers from the following choices, which will evaluate the frequency response of the filter at frequency 0. +]]>
+M = 50; nn = 0:M; +alpha = 2; +GW = exp(-0.5*( ((alpha*(nn-M/2))/(M/2)).^2 )); %-- Gaussian window +wc = 0.3*pi; +sincwc = sin(wc*(nn-M/2))./(pi*(nn-M/2)); %-- sinc function +sincwc(M/2 + 1) = wc/pi; %-- fix divide by zero +bb = sincwc.*GW; %-- Filter Coefficients ++ +Choose all correct answers from the following choices, which will evaluate the frequency response of the filter at frequency "pi". +]]>
+of L = 101. The filter coefficients are stored in the vector bb. +
+Given a signal: +
+xx = cos(2*pi*100*tt) + cos(2*pi*200*tt) + sin(2*pi*300*tt); +
+where tt=-4000:1/10000:4000;
+ +Which commands could be used to pass only the sine and reject the two cosines by +using a bandpass filter? +Note: the BPF would be created from the LPF. +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+yy = conv(bb2,xx) +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = hh.*xx; +]]>
+hh = freqz(bb2,1,-pi:.01*pi:pi);
+yy = conv(hh,xx); +]]>
+yy = conv(bb2,xx) +]]>
+yy = bb2.*xx +]]>
+yy = xx.*hh.*cos(2*pi*300*((0:100)-50)) +]]>
nn = 0:10000; +xx = 99*sin(2*pi*0.25*nn);+Which one of the following will correctly play the sound? +]]>
+SS = struct('type',['A';'B'],'color','red','x',[3 4])
+
+]]>xx = cos(w*t + phi); +]]>
w = interp1(xx,yy,zz), +what do xx, yy, and zz represent? +]]>
yy contains the points at which the function xx is given (independent variable). +
zz is a vector containing the points at which we want to evaluate and interpolate the values of the function xx at. +]]>
yy is the vector representing the function values that we want to interpolate. +
zz is a vector containing the points at which we want to evaluate and interpolate the values of the function yy at. +]]>
zz is a vector containing the points at which we want to evaluate and interpolate the values of the function xx at. +
yy is just a dummy vector. +]]>
xx is a vector containing the points at which we want to evaluate and interpolate the values of the function zz at. +
yy contains the points at which the function zz is given (independent variable). +]]>
+{Equation:eqn=
+{Equation:eqn=
function PreLab10 = mycos(t)
+% MYCOS defines a cosine
+%
+PreLab10 = cos(pi*t);
+Which command will correctly calculate the integral of one period of the cosine? ]]>
What is the correct way to add yy to the LAST 5 points of xx?
The result (called zz) should be 15 points long.
Assume all vectors are row vectors.
Do not assume that zz has been initialized. +]]>
Each string row vector is an array of characters ('0' or '1') in MATLAB, e.g., '0010110101110'. + +
Which of the following is the correct way +to form the bit string sent out from modem? +]]>
+NOTE: you only need to place one of these zeros, because PeZ will automatically include a companion zero at the conjugate location. +]]>
+f(t) = +
t, when (0<= t <2) +
t^2 when (3<= t <=5) +
4*t when (6<= t <=10) +
zero, otherwise + +
+which of the following codes computes correctly the integral of the function defined above over the period [2, 5] using quad8() and inline()? +]]>
+{Equation:eqn=
+{Equation:eqn=
+{Equation:eqn=
+{Equation:eqn=
SS = struct('strings',{{'hello','yes'}},'lengths',[5 3])
+
+]]>x(t) = 8.5cos(2π(350)t +π/3)+]]>
xx = 8.5 cos(2 pi 350 tt + pi / 3);
+]]>
xx = 8.5*cos(2*pi*350*tt) + pi/3;
+]]>
xx = 8.5*cos(2*pi*350*tt+pi/3);
+]]>
xx = 8.5cos(2*pi*8000*tt+pi/3);
+]]>
xx = cos(2*pi*350*tt);
+]]>
+Which of the following zeros does not belong to this filter? +]]>
What is the correct way to add yy to the FIRST 5 points of xx?
The result (called zz) should be 15 points long.
Assume all vectors are row vectors.
Do not assume that zz has been initialized. +]]>
z6 - 1 = 0]]>
b[n] = δ[n-1] + δ[n-2] +Define c[n] = a[n]*b[n] where * denotes convolution. +
What is C(z)?
]]>x[n] = 2 ,for n = 1,2What is the z-transform of this sequence? ]]>
x[n] = 4 ,for n = 3
x[n] = 0 ,otherwise
x[n] = 2δ[n] + 3δ[n-1]is applied. +
What is the output Y(z)? ]]>
h1[n] = 0.5 ( δ[n] + δ[n-1] + δ[n-2] )are cascaded. ]]>
h2[n] = 0.4 ( δ[n] + δ[n-1] )
X(z) = 1 - 2z-1 + 3z-3 +Determine x[n]? ]]>
% Returns a single sinusoid with the key and duration specified
fs = 11025;
tt = 0:1/fs:dur;
f0 = 440*2^((keynum-49)/12);
tone = cos(2*pi*f0*tt);
A student wants to modify the function so that the tone created by this function has TWO frequency components. The new tone should be the sum of two sinusoids, one of which is the fundamental and the other of which has a frequency 2 times higher. The amplitudes (and phases) can be the same. Which one of the following is a correct modification that will accomplish this task? +]]>
tone = cos(2*pi*2*f0*tt); +]]>
tone = cos(2*pi*f0*([1 2]')*tt); +]]>
f0 = f0 + 2*f0; +]]>
tone = cos(2*pi*f0*tt) + cos(2*pi*2*f0*tt) +]]>
y1[n] = ( x[n] + x[n-1] + x[n-2] ) / 3+
and System 2 is described by the system function
H2(z) = 1 + z-2What is the length of the overall cascade system. ]]>
for the pole-zero plot shown below? +]]>
+If the FUNDAMENTAL period is defined to be To = 2*pi, which of the following signals is synthesized (approximately) as N becomes large (>20)? +
NOTE: The Fourier Series coefficients for |k| < N are used in the synthesis. +]]>
h[n] = δ[n] - δ[n-1] + δ[n-2] - δ[n-3]What are the poles of this filter?]]>
+If the FUNDAMENTAL period is defined to be To = 12, which of the following signals is synthesized (approximately) as N becomes large (>20)? +
NOTE: The Fourier Series coefficients for |k| < N are used in the synthesis. +]]>
y[n] = x[n] - x[n-2] + x[n-3]What should bb, the vector of filter coefficients, be defined as? ]]>
h[n] = δ[n] - δ[n-1]What is G(z)? ]]>
b[n] = δ[n] + δ[n-2] ++Define
C(z) = A(z) + B(z) +
+What is C(z)? +
]]>can also be written in the following form
where Re{ } denotes the real operator.How would you define the complex amplitude X in Matlab notation? +]]>
h[n] = δ[n] - 2cos( 0.5π[n-1] ) + δ[n-2]]]>
+ +You can have MATLAB running while you answer these questions.
+ +Check the button below to confirm that you understand these instructions. +]]>
+Whenever you complete an answer, hit the "Save Answer" button.
+When you are finished with all the questions, hit the "FINISH" button.
+]]>
h2[n] = δ[n] + δ[n-2]What is the impulse response of this system? ]]>
z = 0.2 + 0.5j+Which of the following zeros does not belong to this filter? + +]]>
y[n] = δ[n] * δ[n+1]]]>
x[n] = δ[n-2] + 2δ[n-4]What is X(z) when x[n] has been delayed by 2? ]]>
z6 - 1 = 0]]>
b[n] = δ[n-1] + δ[n-2]Define
c[n] = a[n] * b[n]where * denotes convolution. What is C(z)? ]]>
What is the sum of this sequence?
]]>x[n] = 2 for n = 1, 2 +
x[n] = 4 for n = 3 +
x[n] = 0 otherwise +
What is the z-transform of this sequence?
]]>h[n] = δ[n] - δ[n-1]What is G(z)? ]]>
x[n] = 2δ[n] + 3δ[n-1]is applied. What is the output Y(z)? ]]>
b[n] = δ[n] + δ[n-2]Denote
C(z) = A(z) + B(z)What is C(z)?]]>
h2[n] = 0.4 ( δ[n] + δ[n-1] )are cascaded. ]]>
X(z) = 1 - 2z -1 + 3z -3Determine x[n]? ]]>
H2(z) = 1 + z -2What is the length of the overall cascaded system. ]]>
h[n] = δ[n] - 2cos( 0.5 ω[n-1] ) + δ[n-2]]]>
z = x + jywhere the real x and the imaginary y parts are the horizontal and vertical coordinates. ]]>
h2[n] = δ[n] + δ[n-2]+ +What is the impulse response of this system?]]>
What is the equation for x(t)?]]>
Which MATLAB code generated this signal?]]>
spectrogram(xx,512,[],[],fsamp,'yaxis');
