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 semiconductor device for use in transmitting a signal over a conductive path to a receiver, the semiconductor device comprising:
a semiconductor chip; a transmit circuit on the semiconductor chip; the transmit circuit to transmit a first sequence of signal levels representing bits to the receiver, where a rate of change of binary state in the bits in the first sequence represents a first frequency; the transmit circuit also to transmit a second sequence of signal levels representing bits to the receiver, where a rate of change of binary state in the bits in the second sequence represents a second frequency; circuitry to receive programming, the programming being responsive to measurement of the first and second sequences at the receiver.