Patent ID: 7120408
Filing Date: 2006-10-10
Classification: H04L

Abstract:
1. An electrical circuit for detecting a squelch state of a differential signal pair, the differential signal pair having a positive signal line and a negative signal line, the circuit comprising: a first digital-to-analog converter having an analog output; a second digital-to-analog converter having an analog output; a first comparator having a negative input, a positive input, and an output, the analog output of the first digital-to-analog converter driving the negative input of the first comparator, the positive signal line of the differential pair driving the positive input of the first comparator; a second comparator having a negative input, a positive input, and an output, the analog output of the second digital-to-analog converter driving the negative input of the second comparator, the negative signal line of the differential pair driving the positive input of the second comparator; and a logical AND gate having a first and second inputs and an output, the output of the first comparator driving the first input of the logical AND gate, the output of the second comparator driving the second input of the logical AND gate, the logical state of the output of the logical AND gate indicating the squelch state of the differential signal pair when the voltage of the analog outputs of the first and second digital-to-analog converters is a lower squelch threshold voltage.