Modulation

Modulation is the process of varying some characteristic of a periodic wave with an external signals.

Often a high-frequency sinusoid waveform is used as carrier signal to convey a lower frequency signal.

Device that performs modulation is known as a modulator and a device that performs the inverse operation of modulation is known as a demodulator.

Common modulation methods include:

Amplitude modulation (AM), in which the voltage applied to the carrier is varied over time.

Frequency modulation (FM), in which the frequency of the carrier waveform is varied in small but meaningful amounts.

Phase modulation (PM), in which the natural flow of the alternating current waveform is delayed temporarily.

Amplitude Modulation

 

 

 

 

 

 

 

 

 

 

 

In AM modulation, the voltage (amplitude) of the carrier is varied by the incoming signal.
Whenever the Amplitude of the carrier is varied by the modulating signal this sort of modulation is called as Amplitude Modulation.

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Frequency Modulation

Special kind of angle modulation in which the instantaneous frequency of a sine-wave carrier is varied by an amount proportional to the magnitude of the modulating wave.
Either amplitude modulation (AM) or frequency modulation (FM) offers a solution to the important problem of how to impress the message wave to be communicated upon a high-frequency oscillation. However, FM offers important advantages in exchange for extra bandwidth occupancy. Also, FM with negative feedback minimizes noise problems and receiver distortion.

In frequency modulation the instantaneous frequency is linearly proportional to the magnitude of the modulating wave.

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Structure Of Amplitude Modulator

This is the Structure that explains us the amplitude modulation generation.