An optical receiver configuration and method of controlling an optical signal
receiver adjusts a decision threshold to reduce the bit error rate (BER). The receiver
includes a comparator having a data input and a digital data output. An error detection
& correction circuit provides an error signal representative of the number of corrected
"1"s and "0"s in the data output from the comparator. Based on the error signal,
a control circuit modifies the comparator decision threshold in a direction to
reduce the BER of the receiver. Dynamic modification of the decision threshold
may also be accomplished. A total percentage error indicator is preferably used
as the basis of changing the decision threshold value. The total percentage error
indicator may be used to variably adjust the decision threshold by an amount that
varies according to the magnitude of the total percentage error indicator to thereby
more quickly arrive at an acceptable decision threshold and prevent overshoot.
A searching method may also be used to determine the usable range of the comparator
before tuning the decision threshold.
