Abrams M1A1 Laser Rangefinder

Way back in the 80s I worked for GEC Marconi Avionics.  I have no idea why we were asked to do this but we had to design the laser rangefinder receiver for the Abrams tank. Of course in a company that does military work you never get to see the big picture.

Abrams A1M1 (pic from Popular Mechanics)

The design challenge was that the return signal from the laser was so faint that thermal noise in the circuit would swamp the signal.  The design solution was a discrete low noise transistor amplifier, mounted on a peltier cooler to reduce the thermal noise. The output signal was then pushed through a logarithmic amplifier to provide a meaningful signal for the targeting systems.

It was an interesting project and as a new engineer, I found it fascinating and exciting.