What is the main function of an AM detector?
B
Demodulate amplitude variations
D
Convert analog to digital
Analysis & Theory
An AM detector extracts the original audio signal from the amplitude-modulated carrier.
Which of the following is a commonly used AM detector?
Analysis & Theory
The envelope detector is simple and widely used for AM demodulation.
The basic components of an envelope detector are:
A
Transistor and capacitor
Analysis & Theory
An envelope detector typically consists of a diode followed by a resistor-capacitor (RC) filter.
What is the role of the diode in an envelope detector?
A
Blocks high-frequency components
C
Detects and rectifies the modulated signal
D
Converts analog to digital
Analysis & Theory
The diode rectifies the AM signal so the envelope can be followed by the RC circuit.
Which detector is commonly used for FM demodulation?
Analysis & Theory
The slope detector converts frequency variations into amplitude variations, suitable for FM demodulation.
What is a major drawback of a slope detector?
B
It requires a lot of power
C
It has poor linearity and selectivity
Analysis & Theory
Slope detectors are simple but not very linear or selective for FM demodulation.
Which of the following is a better alternative to slope detectors for FM detection?
Analysis & Theory
Phase discriminators (like Foster-Seeley) provide better performance than slope detectors for FM demodulation.
The Foster-Seeley discriminator is used to:
Analysis & Theory
The Foster-Seeley discriminator is a type of FM detector that demodulates the frequency variations in FM signals.
Which FM detector provides good amplitude noise rejection?
Analysis & Theory
The ratio detector is an FM demodulator known for its amplitude noise immunity.
Why is limiting used before FM detection?
B
To enhance frequency deviation
C
To remove amplitude variations
Analysis & Theory
Limiting removes amplitude variations (noise) before FM detection since FM information lies in frequency changes, not amplitude.