Question

Question :
A) Describe how to detect an amplitude modulated wave.
B) Sketch a neat diagram for a detector for AM signal.

Answer 1

Hint:Amplitude modulated: Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio carrier wave. In amplitude modulation, the amplitude (signal strength) of the carrier wave is varied in proportion to that of the message signal, such as an audio signal.

Step by step solution:
a) Following are the steps to detect an amplitude modulated wave.
-Receiving antenna serves as a transducer and converts the received signal into electrical form.
-A low noise and low gain amplifier is used to amplify the signal before processing.
-This is passed through an IF stage where the frequency band is translated down from the carrier frequency to the intermediate frequency.
-It is then passed through a detector which translates the frequency down to the original frequency and demodulation occurs.
-Finally the demodulated signal is passed through an amplifier for large amplification.

b) Block diagram for detector of an AM signal.

Note:While solving these types of questions we must have a clear understanding of amplification, modulation, signals and waves. We should have a clear understanding of all the phases involved in the process of modulation and demodulation then only we can come to a correct result. While making block diagrams many of us take the arrows wrong while these arrows play a vital role in the meaning of the diagram hence we should keep in mind which arrow points which direction.