Modulatsiooninäitajad

Modulatsiooninäitajad, or modulation parameters, are essential characteristics that define how information is encoded onto a carrier signal in telecommunications. These parameters quantify the extent and nature of the modulation process. The specific parameters depend on the type of modulation being used.

For amplitude modulation (AM), the primary modulation parameter is the modulation index, often denoted by 'm'. This dimensionless quantity indicates the degree of variation in the amplitude of the carrier signal relative to its unmodulated amplitude. A modulation index of 1 (or 100%) represents complete modulation, where the envelope reaches zero. Values greater than 1 lead to overmodulation, causing distortion.

In frequency modulation (FM), the key parameters are the frequency deviation and the modulation index. Frequency deviation is the maximum change in the carrier frequency from its resting frequency. The FM modulation index is the ratio of the frequency deviation to the modulating signal's frequency. This index determines the bandwidth required for the FM signal.

Phase modulation (PM) also involves a modulation index, which is related to the phase shift of the carrier signal. The phase deviation is the maximum change in the carrier's phase. The PM modulation index is the ratio of the maximum phase deviation to the amplitude of the modulating signal. While related to FM, PM's index is defined differently.

These modulation parameters are crucial for designing receivers and transmitters, analyzing signal quality, and ensuring efficient and reliable communication. They directly influence signal bandwidth, power efficiency, and susceptibility to noise.