Leica laser range finder , someone opened it?

Did someone opened a Leica laser range finder (one of their new
models)??? , i wonder if they use optoelectronic mixing and what kind
of APD they use for detection. They get +-1.5mm resolution over
100meter. I am thinking of buying one just to see and measure how they
do it...

I managed to do the optoelectronic mixing with good results, the
limiting factor seems to be the thermal noise of the resistor used to
convert the photocurrent into voltage before the voltage amplification.
I use the C30902E APD agt 217V reverse bias, with 5K resistor (its a
smd pot and 5K gave me the best S/N ratio), after this there a couple
cap to reject daylight dc current wereafter there is an OPA656
amplifier with a gain of 2600 (non inverting amp) wereafter an OPA177
with an additional gain of 5 wereafter a LP filter.

In theory the resistor at the input should be as high as possible to
have highest S/R ratio (noise increases with root and signal lineair
with R value) but then biassing of the APD becomes a problem...

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