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: Figure 19 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 %. Curve D is the actual characteristic compared with the ideal (curve A) and the limits (curves B and C). X Figure 19 – Typical frequency fluctuation characteristics
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