Abstract: A transceiver for exchanging data with a transmission channel using any of the 100BaseT2, 100BaseTX, or 100BaseT4 standards, which includes a receive circuit for receiving analog data from the transmission channel. The receive circuit includes a first switch and a first analog-to-digital converter coupled to the first switch. The receive circuit further includes a second analog-to-digital converter coupled to the first switch. There is further included a second switch coupled to the first analog-to-digital converter and to the second analog-to-digital converter. The analog data is switched by the first switch into the first analog-to-digital converter and the second analog-to-digital converter to allow the first analog-to-digital converter and the second analog-to-digital converter to support sampling requirements of any of the 100BaseT2, the 100BaseTX, or the 100BaseT4 standards.

Abstract: An evaluation circuit for use in evaluating the bit error rate (BER) performance of a Viterbi detector based upon a computation of its amplitude error margin (AEM) includes two threshold comparison circuits and an AEM computation circuit. Each threshold comparison circuit receives and compares a Viterbi signal from a Viterbi detector and one or two AEM threshold signals and in accordance therewith generates a comparison signal. The Viterbi signals represent combinations of signals which include the sum of and difference between the Viterbi difference metric and slicer threshold signals associated with the Viterbi detector. The AEM threshold signals correspond to probabilities that the two Viterbi signals have magnitudes which exceed some predetermined values. The AEM computation circuit receives a control signal from the Viterbi detector and the two comparison signals and computes an AEM parameter which corresponds to one of the Viterbi signals.