Unit 5 Flashcards
The process of superimposing an input signal, also called the intelligence signal onto a carrier wave is called___
Modulation
Time is not a form of modulation.
(T or F)
True
This type of modulation changes the voltage of the RF carrier for transmitting
Amplitude
What parts of the intelligence waveform affect the amplitude of the modulated waveform in amplitude modulation?
Amplitude
In amplitude modulation, what are the output signals of the modulator? (3)
Carrier, Upper Sideband, Lower Sideband
In amplitude modulation, the intelligence is carried in the (2)
Upper and Lower Sideband
What type of modulation inefficiently uses bandwidth and power during transmission?
Amplitude
What are 3 advantages of amplitude modulation?
- simple to implement
- can be demodulated using a single diode rectifier
- Cost
List 3 disadvantages of amplitude modulation
- prone to high noise levels
- inefficient use of power
- inefficient use of bandwidth
In amplitude modulation, how much power is found in the carrier?
50%
In Amplitude Modulation, how much power is found in the upper sideband?
25%
In amplitude modulation, how much power is found in the lower sideband?
25%
What are the variants of Single sideband?
LSB SSB
USB SSB
DSB
ISB
AME (amplitude modulated equivalent)
Single Sideband is widely used in the ___ portion of the frequency spectrum.
HF
3 advantages of single sideband
1.Reduction in transmitter power requirements
2.More effective solution for two way radio comm.
3.Reduced receiver bandwidth by half
Disadvantages of single sideband
1.More complex circuits
2.cost more than AM
3. Circuits require more maintenance
What modulation is resilient to noise and interference and used for high quality broadcast transmission?
Frequency
In FM, what parts of the intelligence waveform affect the frequency of the modulated waveform?
Frequency
In FM, the amount the signal deviates above and below the center frequency is known as___
deviation
2 methods to generate frequency modulated signals
Varactor Diode Oscillator
Phase Lock Loop
The FM demodulator may also be called
detector or discriminator
3 advantages of FM
1.Resilient to noise and interference
2.Easy to apply modulation at low power stage of the transmitter
3.Use of non-linear RF amplifiers are more efficient than the linear
3 disadvantages of FM
Poor spectrum efficiency
Complicated circuits
Some modes have higher spectrum requirements
Binary digit, logic 1 or 0
Bit