There are _______  number of modulation techniques.

There are _______  number of modulation techniques.

Right Answer is:

3

SOLUTION

When it is required to transmit digital data over a band-pass channel, it is necessary to modulate the incoming data onto a carrier wave (usually sinusoidal with fixed frequency limits imposed by the channel. The data may represent digital computer outputs or PCM waves generated by digitizing voice or video signals. The channel may be a telephone channel, microwave radio link, satellite channel, or optical fiber.

 In any event, the modulation process involves switching or keying the amplitude, frequency, or phase of the carrier in accordance with the incoming data. Thus there are three basic modulation techniques for the transmission of digital data; they are known as

  1. Amplitude shift keying (ASK)
  2. Frequency-shift keying (FSK)
  3. Phase-shift keying (PSK)

The above techniques can be viewed as special cases of amplitude modulation, frequency modulation, and phase modulation respectively.

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