Patent ID: 7577212
Filing Date: 2009-08-18
Classification: H04L

Abstract:
1. A system for setting a reference voltage applied to a first input of a differential receiver having a second input for receiving a digital signal, the system comprising: a reference voltage generator providing a reference voltage coupled to the first input of the receiver, the reference voltage generator having an adjustably selectable magnitude; a test generator for generating a digital test signal coupled to the second input of the receiver, the digital test signal having predetermined characteristics; a data analysis logic coupled to an output of the receiver, the data analysis logic analyzing an output signal from the receiver to determine if the test signal is properly being coupled through the receiver, the data analysis logic comprising a pattern recognition logic coupled to receive the output signal from the receiver, the pattern recognition logic being operable to determine if the output signal has the predetermined characteristics, the data analysis logic further comprising a flip-flop having a data input coupled to receive the output signal from the receiver and a clock input coupled to receive a clock signal, the flip-flop capturing the output signal from the receiver responsive to the clock signal, the pattern recognition logic being coupled to an output of the flip-flop; and a calibration logic coupled to the reference voltage generator and the data analysis logic, the calibration logic selecting a final value for the reference voltage based on the analysis of the output signal from the receiver, the calibration logic causing the reference voltage generator to couple the final value of the reference voltage to the first input of the receiver.