[Laser] PIN diodes and Noise floor
Glenn Thomas
[email protected]
Fri, 18 Apr 2003 22:21:37 -0700
Hi Andy.
I think that subtracting the dark current (to the extent that you know what
it is) will improve your signal to noise ratio. This is solely because it
will reduce the amount of noise due to dark current, leaving whatever other
noise sources you have to deal with.
73 de Glenn
At 06:12 PM 4/18/03 -0400, you wrote:
>I have a question for folks who have played around with PIN diode detectors--
>
>I've put together a few of the K3PGP front ends now and I'm really looking
>forward to getting my laser diodes going for a complete tranceiver
>system. Anyway, I was wondering if the PIN diode dark current is much of
>a factor under actual nightime use? Is the noise floor coming from
>ambient light or from the diode itself? I imagine this will depend
>largely on how big of a lens you are using, and how clear the sky is, but
>I'm trying to get a ballpark figure. John mentions that cooling the diode
>improved the NF, e.g. putting it in the freezer for a while, but does that
>really matter practice? Does ambient light drown out the dark
>current? I'd test this myself, but it's not easy for me to get away from
>city lights.
>
>Andy K0SM/2
>
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