System and method for internal AC coupling with active DC restore and adjustable high-pass filter for a PAM 2/4 receiver

摘要

A receiver termination circuit includes an internal AC coupling capacitor and an adjustable resistor forming an adjustable high-pass filter (HPF) at a receiver side of a transmission medium, and a digital-to-analog converter (DAC) coupled to the adjustable HPF, the DAC configured to provide a signal having a low-pass filter response to the adjustable HPF to provide a DC restore function.

主权项

1. A receiver termination circuit, comprising:
an internal AC coupling capacitor and an adjustable resistor forming an adjustable high-pass filter (HPF) at a receiver side of a transmission medium; and a digital-to-analog converter (DAC) coupled to the adjustable HPF, the DAC configured to provide a signal having a low-pass filter response to the adjustable HPF to provide a DC restore function, wherein an RC characteristic of the adjustable HPF is adjustable by operation of the DAC and the adjustable resistor, and wherein the DC restore function provided by the DAC comprises digital feedback inserting receive data at frequencies in the range from DC to a high pass cutoff frequency set by an adjustable high-pass filter (HPF).