What is the minimum frequency deviation in frequency modulation required to transmit intelligible signals?

In frequency modulation (FM), the minimum frequency deviation required to transmit intelligible signals is typically at least 1 kHz. This deviation refers to the extent to which the carrier frequency can shift from its resting frequency in response to the amplitude of the audio input signal.

This minimum requirement ensures that the modulation process can create clear enough changes in frequency that the receiving equipment can effectively demodulate the signal and reproduce the original audio waveform. A deviation of at least 1 kHz is generally sufficient to encode the audio information adequately, providing a reasonable balance between sound quality and the required bandwidth for transmission.

Higher deviations can improve signal robustness and fidelity but are not strictly necessary for intelligibility. Therefore, the answer reflects a fundamental characteristic of FM transmission concerning maintaining clarity in voice or audio signals.