Receiver for optical signals, with a preamplifier providing dc-offset correction, and a dual mode transimpedance amplifier

摘要

A digital data receiver comprises a pre-amplifier for receiving a digital data input signal and a correction signal to produce a data output signal. A dc offset cancelling circuit is responsive to the data output signal for generating the correction signal to cancel dc offset contained in the digital data input signal. A post-amplifier receives the data output signal from the pre-amplifier and a reference signal. A peak detector is responsive to an output of the post-amplifier for detecting a peak amplitude thereof and generating the reference signal so that the post-amplifier has a first gain value during the time the data input signal is absent or less than its peak amplitude, and a second gain value approximately equal to twice the first gain value for a predetermined time after the peak amplitude of the data input signal is reached. The post-amplifier and peak detector have substantially equal operating characteristics.