Patent ID: 6108528
Filing Date: 2000-08-22
Classification: H03K,H04L

Abstract:
A squelch circuit comprising:programmable control means for adjusting a threshold voltage; andreceive squelch circuit means for determining whether an input data signal has a prescribed pulse width, wherein the receive squelch circuit means detects a pulse width of the input data signal and compares the input data signal pulse width to a standard pulse width to determine whether the input data signal has the prescribed pulse width, wherein the receive squelch circuit means comprises,first and second current sources coupled to a first reference voltage each supplying a predetermined amount of current based on a supplied power,first and second transistors that detect a pulse width of a corresponding input data signal, wherein the first and second transistors respectively have first electrodes connected to the first and second current sources, control electrodes connected to receive the input signal, and second electrodes coupled to a second reference voltage,first and second capacitors respectively connected between the first electrodes of the first and second transistors and the second reference voltage, andfirst and second voltage comparators that compare one of the detected pulse widths received from the first and second transistors with a prescribed value to judge whether the detected pulse width has the prescribed pulse width.