Question

With the help of a functional block diagram, Explain the operation of a superheterodyne AM receiver.

Answer 1

Superheterodyne is defined as the process of designing such kinds of Radio Receivers which works by coupling two frequencies together.

Complete step by step solution:
The block diagram of superheterodyne AM (Amplitude Modulated) receiver is given in the below figure:

The block diagram of the superheterodyne AM receiver consists of the following:
1. Receiving Antenna is a device that is used for the reception of signals (also known as Radiofrequency).
2. RF Amplifier is used to amplify (i.e. increase the amplitude) of the signals received by the receiving antenna.
3. The local Oscillator produces a frequency for the mixer to superimpose it with RF Frequency.
4. The mixer receives the output from both RF Amplifier and the Local Oscillator and then combines them which is then called the intermediate frequency (IF).
5. IF Amplifier takes the Intermediate Frequency from the Mixer and Amplifies the input.
6. A detector is a device that receives input from the IF Amplifier and couples it with the input of the detector.
7. AF (Audio Fidelity) Amplifier amplifies the output of the detector.
8. Loud Speaker finally converts the electronic signals to sound waves.

Working of superheterodyne AM receiver:
A superheterodyne amplitude modulated receiver consists of an antenna, RF Amplifier, Local Oscillator, and Mixer, IF Amplifier, Detector, AF Amplifier, and Loud Speaker. The incoming signal through the antenna is first filtered in order to remove noise and then fed to RF Amplifier which then amplifies it. The output from the RF Amplifier is coupled with that of the Local Oscillator in the mixer. The output from the mixer is then amplified by the IF Amplifier and then fed into the Detector. Detector then couples the output from the IF Amplifier and the input of the detector itself which is then fed to the Loud Speaker. Finally, Loud Speaker converts the electronic signals to sound waves.

Note: In order to solve such theoretical kinds of questions, one must have a clear conceptual understanding of Sound Chapter.