Patent ID: 6115430
Filing Date: 2000-09-05
Classification: H04L

Abstract:
A differentiating circuit comprising:a differential input buffer for generating a non-inverted signal and an inverted signal from a Non Return to Zero (NRZ) code input signal, and respectively transmitting the non-inverted signal and the inverted signal;a delay circuit for generating a first differentiated waveform by combining said non-inverted signal output to one terminal and said inverted signal input to a remaining terminal and delayed, and generating a second differentiated waveform by combining said inverted signal input to said remaining terminal and said non-inverted signal input to said one terminal and delayed;a differential output buffer for transmitting said first and second differentiated waveforms generated by said delay circuit to output terminals;a lowpass filter for removing unwanted resonant frequency components at the output side of said differential output buffer;a rectifying circuit at the output side of said lowpass filter for rectifying an output signal from the lowpass filter, and generating a rectified signal having a clock component; anddifferential matching means for removing signal reflection between the output side of said lowpass filter and said rectifying circuit, whereina delay line length of said delay circuit is set so that unwanted resonant frequency components generated due to impedance mismatching between the impedance of said differential input buffer and the impedance of said delay circuit are not close to the input signal frequency.