Unit 2: AM Reception in Analog Communication - SY(E&TC) AY 2023-24

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Questions and Answers

What is the main purpose of the AGC (Automatic Gain Control) circuit in a superheterodyne receiver?

To recover the original modulating signal from the highly amplified IF signal
To increase the voltage and power of the recovered signal for driving a speaker
To maintain a constant output voltage level over a wide range of RF input signal levels (correct)
To automatically adjust the tuning of the RF amplifier to match the incoming signal frequency

How does the AGC circuit work to maintain a constant output voltage level?

The AGC circuit rectifies and filters the recovered signal to produce a DC voltage, which is then fed back to the IF and RF amplifiers to control their gain (correct)
The AGC circuit monitors the frequency of the incoming signal and tunes the RF amplifier to match it, maintaining a constant output level
The AGC circuit measures the power of the output signal and adjusts the gain of the audio and power amplifiers accordingly
The AGC circuit uses a feedback loop to increase the gain of the receiver when the input signal is weak, and decrease the gain when the input signal is strong

What is the purpose of the RF (Radio Frequency) amplifier in a superheterodyne receiver?

To increase the voltage and power of the recovered signal for driving a speaker
To amplify the incoming RF signal before it is mixed with the local oscillator signal (correct)
To filter out unwanted frequencies from the incoming RF signal before it is mixed
To recover the original modulating signal from the highly amplified IF signal

What is the role of the IF (Intermediate Frequency) amplifier in a superheterodyne receiver?

To provide high gain amplification to the frequency-converted IF signal (B) Signup and view all the answers

How does the AGC circuit prevent distortion in a superheterodyne receiver?

By reducing the gain of the IF amplifiers when a high-amplitude input signal is present, preventing overload and distortion (D) Signup and view all the answers

What is the purpose of the local oscillator in a superheterodyne receiver?

To generate a fixed-frequency signal that is mixed with the incoming RF signal to produce the intermediate frequency (IF) (A) Signup and view all the answers

How does the RF amplifier in a superheterodyne receiver help to improve the overall performance of the receiver?

By amplifying the incoming RF signal before it is mixed with the local oscillator signal, improving the signal-to-noise ratio and sensitivity of the receiver (D) Signup and view all the answers

What is the role of the detector circuit in a superheterodyne receiver?

To recover the original modulating signal from the highly amplified IF signal (C) Signup and view all the answers

How does the AGC circuit help to maintain the dynamic range of a superheterodyne receiver?

By reducing the gain of the IF amplifiers when a high-amplitude input signal is present, and increasing the gain when the input signal is weak, maintaining a constant output level (C) Signup and view all the answers