### Modulation Techniques: Amplitude, Frequency and Phase modulation | Soukacatv.com

Posted May 28, 2019 by tracyhe

Modulation techniques are methods that are used to encode digital information in an analog world. The 3 basic modulation techniques are as follows: a.AM (amplitude modulation),b.FM (frequency modulation),c.PM (phase modulation).

Modulation techniques are methods that are used to encode digital information in an analog world. The 3 basic modulation techniques are as follows:

a. AM (amplitude modulation)

b. FM (frequency modulation)

c. PM (phase modulation)

All 3 modulation techniques employ a carrier signal. A carrier signal is a single frequency that is used to carry the intelligence (data). For digital, the intelligence is either a 1 or 0. When we modulate the carrier, we are changing its characteristics to correspond to either a 1 or 0.

AM - Amplitude Modulation

Amplitude Modulation modifies the amplitude of the carrier to represent 1s or 0s.In the above example, a 1 is represented by the presence of the carrier for a predefined period of 3 cycles of carrier. Absence--or no carrier--indicates a 0.

· Simple to design.

· Noise spikes on transmission medium interfere with the carrier signal.

· Loss of connection is read as 0s.

FM - Frequency Modulation

Frequency Modulation modifies the frequency of the carrier to represent the 1s or 0s. In the above example, a 0 is represented by the original carrier frequency, and a 1 by a much higher frequency (the cycles are spaced closer together).

· Immunity to noise on transmission medium.

· Always a signal present. Loss of signal easily detected

· Requires 2 frequencies

· Detection circuit needs to recognize both frequencies when signal is lost.

PM - Phase Modulation

Phase Modulation modifies the phase of the carrier to represent a 1 or 0.

The carrier phase is switched at every occurrence of a 1 bit, but remains unaffected for a 0 bit. The phase of the signal is measured relative to the phase of the preceding bit. The bits are timed to coincide with a specific number of carrier cycles (3 in this example = 1 bit).

· Only 1 frequency used

· Easy to detect loss of carrier

· Complex circuitry that is required to generate and detect phase changes.

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Source: epq
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 Contact Email [email protected] Issued By Tracy He Phone 13410066011 Country China Categories Business , Manufacturing , News Tags analog modulator , china digital modulator manufacturer , digital modulator , digital modulator manufacturer , digital modulator supplier , encoder modulator , hd rf modulator , hdmi encoder modulator Last Updated May 28, 2019