A signal detector includes, in part, first and second peak detectors, a comparator and an amplifier. The first peak detector generates a first signal in response to receiving an incoming signal. The second peak detector generates a second signal in response to receiving a threshold signal. The comparator generates an output signal representing the detected signal in response to the first and second signals. The amplifier amplifies the difference between the second signal and a reference voltage and, in response, generates a control signal that controls the gain of the first and second peak detectors. Each of the first and second peak detectors optionally include a differential amplifier and a pair of common-gate amplifiers each coupled to one of the output terminals of its associated differential amplifier. An RC network may be coupled to a common terminal of the first and second common gate amplifiers of each peak detector.
CROSS-REFERENCES TO RELATED APPLICATIONS
The present application claims benefit under 35 USC 119(e) of U.S. provisional Application No. 60/675,526, filed Apr. 27, 2005, entitled "Method And Apparatus For Detection Of High-Speed Electrical Signals," the content of which is incorporated herein by reference in its entirety.
A peak voltage detector is used to detect the absolute value of the peak differential amplitude of a differential input signal. The peak voltage detector includes a differential amplifier receiving the differential input signal and generating a corresponding pair of differential output signals. The voltage detector also includes a capacitor on which an output signal is generated. A first differential comparator generates a first signal whenever the differential voltage from the differential amplifier is greater than the voltage of the output signal. A second differential comparator generates a second signal whenever the negative of the differential voltage from the differential amplifier is greater than the voltage of the output signal. A current source applies current to the capacitor responsive to receiving either the first or second signal. The amplitude of the feedback voltage is thus equal to the absolute value of the peak differential amplitude of the input signal.
