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Question
Why is Modulation index kept low?
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Solution
As the low-frequency modulating signal is mixed with a high-frequency carrier wave, the distortion is restricted due to the high-frequency carrier wave for modulation index lying between 0 and 1. If the amplitude of modulating wave is greater than the carrier wave then the carrier wave gets over-modulated. This over modulation results in distorted waveform envelope which will result in a distorted output signal.
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