Digital transmitter

摘要

An equalizer provided in a digital transmitter compensates for attenuation in a signal channel to a digital receiver. The equalizer generates signal levels as a logical function of bit history to emphasize transition signal levels relative to repeated signal levels. The preferred equalizer includes an FIR transition filter using a look-up table. Parallel circuits including FIR filters and digital-to-analog converters provide a high speed equalizer with lower speed circuitry. The equalizer is particularly suited to in-cabinet and local area network transmissions where feedback circuitry facilitates adaptive training of the equalizer.

主权项

1. A non-transitory computer-readable medium storing a representation of a circuit comprising:
transmitter circuitry to receive input bits and to responsively generate a serial output signal having a sequence of signal levels; where
the transmitter circuitry includes a filter having at least three taps, each tap driven responsive to respective ones of the input bits, andthe filter is to attenuate signal levels in the serial output signal representing no variation between adjacent input bits relative to variation between the adjacent input bits, such that signal levels in the serial output signal are emphasized for bits that represent transitions in logic level between adjacent ones of the inputs bits relative to bits that do not represent transitions in logic level between the adjacent ones of the input bits.