Amplitude Modulation Flashcards
(23 cards)
What are the three main types of modulation?
Amplitude
Frequency
Phase
Define Modulation
The process by which information is superimposed onto a carrier wave so as to send it a greater distance.
Define the Modulating Wave.
The waveform of the original intelligence.
Define the Carrier Wave.
The waveform that is used to carry the information contained in the Modulating Wave, it is the signal you centre to and the one that is actually sent.
What is another term for the carrier frequency?
RF or Radio Frequency
Define Amplitude Modulation.
The method whereby the amplitude of the Modulated Wave is varied in accordance with the amplitude of the Modulating Wave.
The outline shape of the Amplitude Modulated frequency is referred to as?
The envelope.
What is it referred to as when the envelope amplitude stays the same?
A constant envelope
What is it referred to as when the envelope amplitude changes repetitively?
A periodic envelope
What is Fm?
The Modulating Wave.
What is “fc”?
The Carrier Frequency.
What is “fc+fm”
Upper Side Band
What is the Lower Side Band rendered to as?
“fc-fm”
How is the power of an Amplitude Modulated Wave spread?
Evenly amongst the sidebands.
What do the two sidebands have in common?
They are mirror images of each other in amplitude.
What is the envelope more of than an instantaneous measurement?
A trend
What is the Depth of Modulation?
A ,easier or ho much the “fm” affects the “fc”, as a percentage.
What is the formula for calculating the Depth of Modulation?
Peak AF Voltage / Peak RF Voltage 100 = DoM%
What states can a Carrier Frequency (fc) be in?
Full or Suppressed
How would a Double Side Band with a Suppressed Carrier be noted in a log?
DSBSC (Double Side Band Suppressed Carrier
Name any two disadvantages of Double Side Band transmissions.
Wasteful on power
Excessive bandwidth
Prone to selective fading
In simple terms, how is a Single Side Band transmission produced?
A Double Side Band is created, and one Side Band is then stripped off before transmission.
What is an advantage of a SSB?
All of the power can be used on one side band
