Question

Assertion: The simplest form of AM demodulator consists of a diode which is configured to act as an envelope detector.
Reason: The product detector can provide better-quality demodulation with additional circuit complexity.
(A) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
(B) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
(C) Assertion is correct but Reason is incorrect.
(D) Both Assertion and Reason are incorrect.

Answer 1

Hint: An envelope detector is an electronic circuit which can be used to demodulate a previously modulated signal including an AM signal. A product detector is a more complex circuit which can also be used for Amplitude demodulation.

Complete step by step solution:
A Modulated radio frequency wave or signal is obtained by allowing a low frequency signal (from an AM radio station for an example) to be superimposed on a carrier wave usually of higher frequency so it can be carried afar and then detected by an antenna connected to a circuit designed to detect this frequency.
In general, the diode is a device which allows current to flow in one direction. When a previously amplitude modulated radio frequency wave, which has a waveform that fluctuates both in the positive direction and in the negative direction at the same time, is allowed to be received by a radio antenna and then allowed to go through a diode, the diode rectifies this modulated signal. This leaves either the negative part or the positive part of the waveform and cuts off the other part. This stage, called rectification stage, is the first state of detection. The resulting output is then filtered out by a capacitor configured such that it filters out high frequency carrier waves and leaves the low frequency audio.
Thus, the diode configured as an envelope detector is an AM demodulator.
In a more complicated fashion, a product detector also provides demodulation of an AM signal, however, independently of the envelope detector as two of them are totally two different configurations of circuit.
Hence, we can conclude that both statements are true, but the reason is not the correct explanation for the assertion.
Thus, the correct option is B.

Note:
In real world application, better and more sophisticated detectors are used for better filtering. Also, the diode detector can only receive one AM station at a time. In reality, radios are designed with much complex circuits to receive all stations at a time.