APPARATUS AND METHODS FOR LOSS OF SIGNAL DETECTION

摘要

Apparatus and methods for loss of signal detection are provided. In one embodiment, a detection circuit for monitoring an input includes a small signal boost circuit, a rectifier circuit, a low-pass filter, and one or more comparators. The small signal boost circuit can generate an amplified signal by providing a first amount of gain to an input signal when the input signal is relatively small, but can saturate and provide reduced gain without external gain control adjustment when the input signal does not have a relatively small magnitude. The rectifier circuit can rectify the boosted signal to generate a rectified signal, and the low-pass filter can filter the rectified signal to generate a filtered signal. The one or more comparators can compare the filtered signal to one or more decision threshold voltages to determine the presence or absence of the input signal on the input.

主权项

1. An apparatus comprising:
a detection circuit configured to monitor an input, wherein the detection circuit comprises:
a first gain circuit operatively coupled to the input and configured to provide gain from input to output to generate an amplified signal, wherein the first gain circuit is configured to provide at least a first amount of gain for input signal levels smaller than a first level, wherein the first gain circuit is configured to saturate to reduce gain from the first gain amount without external gain control adjustment for input levels higher than a second level, wherein the second level is higher than the first level;a first rectifier circuit configured to rectify the amplified signal to generate a rectified signal;a first low-pass filter configured to filter the rectified signal to generate a filtered signal; andone or more comparators configured to evaluate the filtered signal to determine a presence or absence of a differential signal at the input.