Theory of Frequency-Modulation Noise

The energy spectrum of frequency-modulation noise is computed for different ratios of signal to noise. Numerical values are given for some simple filter amplitude characteristics. The theory is based on the Fourier concept of noise and treated in three steps: no signal, signal without modulation, and modulated signal. The result is given in the form of a series, and it is shown that this development is convergent. The suppression of the modulation by noise is also discussed.