Amplitude Modation Flashcards
Modulation definition
“Modulation is the process of adding baseband information to and modify a higher frequency continuous waveform, the carrier, so as to make the info signal more compatible with the medium used to transmit.”
Carrier definition
“A carrier is a high frequency continuous waveform”
Why is AM used in aviation
Fm suffers from ‘capture effect’ meaning a stronger fm signal will drown the weaker one
AM allows a weaker signal to be heard
How many kHz between each radio channel
10
Advantages of am broadcasting
Simplicity of tech
Wide coverage
Easy to demodulate
Broadcasting range
Disadvantages of am Broadcasting
Poor sound quality
Limited bandwidth
Energy inefficient
FM advantages
Superior sound quality
High signal-noise ratio
Efficient use of bandwidth
Fm disadvantages
Limited coverage range
Complexity and cost
Higher power requirements
Fm uses
Radio broadcasting
Telecommunications
Tv sound
Wireless headphones
How to produce fm
Simplest way is to use a vco ( voltage controlled oscillator )
Modulation index definition
“Modulation index is the measure of the extent by which a carrier is varied by the information signal”
Wideband fm =
Fm broadcast
Narrow band fm =
Voice comms
