Amplifier for integrated laser/FLIR rangefinder

Abstract

An integrated laser/FLIR rangefinder has a laser energy detector generating an electrical signal in response to impinging laser energy, a preamplifier for amplifying the signal and a post amplifier for selectively shaping the signal output of the preamplifier. The preamplifier has a plurality of transistors connected in parallel provided for substantially reducing noise, a summing circuit sums the outputs of the plurality of transistors, and a trans-resistance amplifier produces a low impedance voltage difference output. The post amplifier includes a delay line and an operational amplifier having a positive terminal and a negative terminal. The positive terminal of the operational amplifier and a first end of the delay line are connected to the trans-resistance amplifier for delaying the output of the trans-resistance amplifier. A second end of the delay line is connected to the negative terminal of the operational amplifier. The operational amplifier combines the delayed and undelayed output of the trans-resistance amplifier and produces a spiked-type difference voltage signal. A low noise frequency compensation circuit allows detectors with what is normally considered inadequate bandwidth to be used to detect the laser return pulses and still produce a reasonably fast pulse with a low noise-level suitable for rangefinding.

Dependencies are inferred from the claim text.