High dynamic range detector for indicating the quieting level of an FM receiver

Claim 1

Detector means for producing a DC output signal representative of the quieting level of an FM receiver, said receiver exhibiting a predetermined quieting response which is a nonlinear function of the level of AC signal processed by said receiver, said detector comprising: first and second linear amplifiers, each exhibiting a predetermined gain characteristic, coupled in cascade configuration with the output of said first amplifier coupled to the input of said second amplifier; coupling means for coupling the receiver processed AC signal, prior to any limiting stages of said receiver, to the input of said first linear amplifier; detector means for producing a pair of DC output signals representative of the magnitude of the signals from said first and second amplifiers, respectively; piecewise linear amplifier means for amplifying each of said detector means produced DC signals by a predetermined gain characteristic corresponding to the quieting response of the receiver, said predetermined gain characteristic being a piecewise linear function of the level of said detector produced output signals; and summing means for summing the piecewise linear amplified signals in a predetermined proportion to produce a DC signal which is linearly related to the quieting level of the receiver.