Patent ID: 7277477

Claim:
A method for performing adaptive pre-emphasis, where a receiver and transmitter are coupled by a serial back channel, with data transmitted on the serial back channel including control codes, with a particular control code having a plurality of additional control code versions, and with the transmitter including an N-parameter transmit filter for implementing pre-emphasis on transmitted data, and with the N-parameter transmit filter having an adjustable parameter value for each of (N−1) parameters, the method comprising the acts of: at the receiver, inserting a first additional control code version, instead of the particular control code, into the serial back channel to encode an increase or decrease to the value of a selected parameter of the N-parameter transmit filter; and at the transmitter, responding to the first additional control code version, when received, to increase or decrease the value of the selected parameter of the transmit filter encoded by the additional control code.