Abstract: A quantizer system for transforming an input signal into an appropriate one of two logic levels. The system compares the received input signal with a threshold voltage and provides an output signal at one of the two logic levels when the input signal exceeds the threshold voltage and at the other of the two logic levels when the input signal is less than the threshold voltage. Circuitry is provided to generate the threshold voltage at a level which is the midpoint of the input signal range. This circuitry includes a feedback loop around a differential amplifier to one input of which is applied the input signal. The feedback loops includes two peak detectors feeding an operational amplifier, the output of which is applied to the other input of the differential amplifier.