| measure of the transfer characteristic of a modulation system as compared to an ideal (straight line) function, usually expressed as an allowable non-linearity in per cent of the specified full range deviation|
Note 1 to entry: Modulation linearity can also be expressed in terms of the permissible distortion of base-band signals produced by the modulation device (for example, intermodulation and harmonic distortion products shall not exceed –40 dB relative to the total modulating signal power).
Note 2 to entry: Figureá19 is a plot of the output frequency of a typical modulated oscillator specified to have a modulation characteristic of 133,3 Hz/V over a range of ▒ 3 V, with an allowed non-linearity of ▒ 5 %. CurveáD is the actual characteristic compared with the ideal (curve A) and the limits (curves B and C).
Figure 19 – Typical frequency fluctuation characteristics