Bipolar threshold detector

Claim 1

A circuit for producing an output signal representative of bipolar excursions of input signals beyond a preset range comprising: an operational amplifier having a first input terminal, a second input terminal, and an output terminal formed with associated circuitry for producing a quiescent positive output signal when a combined signal impressed on said first input terminal is positive with respect to a total signal impressed on said second input terminal, and, for passing a negative output signal when said total signal is positive with respect to said combined signal; a circuit input terminal having means for converting said bipolar input signals to representative bipolar currents; a diode network coupling said circuit input terminal to said amplifier being adapted for blocking said bipolar currents representative of signals within said preset range and for passing greater said bipolar currents to said second input terminal and for passing lesser said bipolar currents to said first input terminal; a negative sink coupled to transfer a negative sink current to said sEcond input terminal; a positive source coupled to deliver a positive current to said first terminal for ensuring said quiescent positive output signal as said diodes block said bipolar currents representative of said preset range; first means connected between said first input terminal and ground for summing said lesser said bipolar currents and said positive current to create said combined signal; and second means connected between said second input terminal and ground for summing said greater said bipolar currents and said negative sink current to create said total signal to ensure said negative output signal when said total signal is positive with respect to said combined signal.