# What is amplitude modulation?

Amplitude modulation:

Amplitude modulation is the process of varying theamplitude of the carrier signalin accordance with theamplitude of the message signal. One important parameter associated with AM is the modulation index (ï½). Modulation index is the ratio of amplitude of message signal to that of the carrier signal.

That is,

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Practically, modulation index is kept less than or equal to 1, to avoid distortion of signals.

Amplitude modulated signals can be produced by adding the carrier signal with the message signal and passing the resultant signal through a square law device (eg: FET). Then the signal from the square law device is passed through band pass filter to allow only the signals centered at carrier frequencies to pass. The output of the band pass filter is power amplified and transmitted by the antenna.

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As you know, modulation is the process of varying one or more properties of a high frequency carrier signal, with respect to the message signal. Different types of modulation are: amplitude modulation (AM), frequency modulation (FM) and phase modulation (PM).

Amplitude modulation:

Amplitude modulation is the process of varying theamplitude of the carrier signalin accordance with theamplitude of the message signal. One important parameter associated with AM is the modulation index . Modulation index is the ratio of amplitude of message signal to that of the carrier signal.

.

Practically, modulation index is kept less than or equal to 1, to avoid distortion of signals.

Amplitude modulated signals can be produced by adding the carrier signal with the message signal and passing the resultant signal through a square law device (eg: FET). Then the signal from the square law device is passed through band pass filter to allow only the signals centered at carrier frequencies to pass. The output of the band pass filter is power amplified and transmitted by the antenna.

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In amplitude modulation the amplitude of carrier wave is varied in accordance with the amplitude of modulaing signal however the frequency of resultant amplitude remains same as that of carrier wave.
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Amplitude modulation is that in which the amplitude changes with respect to time
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Amplitude modulation

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