摘要 |
An input digital signal developed by a signal source e.g. a photodiode is time-averaged and mirrored by a current mirror to generate one or more decision thresholds. The thresholds may be a set or variable fraction of the average current and track any variation in the average current. This obviates the need for limiting or AGC amplifiers that would otherwise be necessary to maintain the input signal level constant if the thresholds were fixed. |