Amplitude modulation

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Aim:-

 To Study the amplitude modulation and determine the depth of modulation.

 

Requirements:-

 Amplitude modulation kit, connecting probes, CRO, etc.

 

Theory:-

 In amplitude modulation, the amplitude (signal strength) of the carrier wave is varied in proportion to that of the message signal being transmitted.

This technique contrasts with frequency modulation, in which the frequency of the carrier signal is varied, and phase modulation in which its phase is varied.

In amplitude modulation the ratio between the amplitude of the modulating wave (vm) to the amplitude of carrier wave is known as depth of modulation. Depth of modulation specifies the amount of energy of carrier wave used in the modulation.

It is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave.

 

Procedure:- 

 1) Check the instruments before connecting.

2) Check the connections as shown in the circuit diagram.

3) Switch on the power supply and function generator and cathode-ray oscilloscope.

4) Set the frequency at 1.5 kHz and vary the amplitude and measure amplitude signals in CRO.

5) Repeat the step-4 for different amplitude.

6) Plot the modulation waves as in CRO.

7) Write the result.

Nature of Graph:-


Tabular column:-


 

Sl.No

 Amplitude

 Modulation Index

 A

 B

 Ma=A-B/A+B × 100

 

 

 

 

 

 

 

 

 

 

 

 


Result:-

We have studied the amplitude modulation and calculated the modulation index (or) Depth of modulation and traced the output wave i.e. amplitude modulation wave.


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