Correction circuit to prevent baseband IF modulation distortion - removes differential phase or gain distortion in FM radio channels

摘要

The connection circuit is used to reduce baseband IF modulation distortion. The distortion arises from differential phase distortion and dynamic differential gain distortion in radio channels in FM systems. A static IF modulation spectrum of order n is produced from the baseband signal using a circuit with non-linear characteristics of order n+1. The resulting spectrum is differentiated once and/or twice and then added to the baseband signal spectrum. Distortion of the baseband IF modulation spectrum due to differential phase and/or gain (order n) distortion is prevented by controlling the level of the converted spectrum. The differentiating systems (D1) and (D2) are used.