Digital signal level overload system

摘要

A signal overload circuit for use in e.g. a digital TV receiver includes a piecewise linear weighting circuit which weights samples of greater magnitude proportionately more heavily than samples of lesser magnitude. The weighted samples are applied to an accumulator, and the accumulated value over a field interval is compared to an overload reference value to generate an overload output signal which is combined with other gain factors for application as the common gain control signal to a common amplifier. The overload detector is coupled in a feedback loop around the common amplifier. In order not to defeat the function of the other gain factors, the overload detector is programmable and its sensitivity is made responsive to the other gain factors.