Sunday 25/06/17

FM Spectrum (Sidebands) Calculator



This calculator predicts the spectrum (sideband levels) due to FM (Frequency Modulation). The results are valid for sinewave modulation only. Applications include calibration of modulators.

It should be noted that a real system with non sinusoidal modulation, or with distortion in the modulator, will generally show increased sideband levels. For a pure FM signal, RF compression does NOT affect sideband levels.

Enter values for Fd (the deviation) and Fm (the modulation frequency). The program assumes identical units, and hence it is not necessary to enter any. The calculated spectrum includes products up to the ninth order. Product order "0" represents the carrier signal.

Modulation Parameters
Deviation, Fd:
Modulating frequency, Fm:
Modulation Index, M:
Product Order 0 1 2 3 4 5 6 7 8 9
Level, dBc:
UK: 01545 560069
International: +44 1545 560069