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Old May 13th 08, 05:49 PM posted to rec.radio.amateur.homebrew
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Default noise source question
wrote:
On 13 Mag, 02:17, RFI-EMI-GUY wrote:
wrote:
Hello,
I'm willing to make a noise source from an UHF transistor (B-E
junction reverse polarized like a zener) and I was wondering if it's
ok to use the output attenuator as part of the resistor network for
the DC bias of the transistor (or zener). I'd probably look at the
arrl handbook if I had it ;-)
Thanks
Francesco IZ8DWF
I would think that your biasing of the resistor network would create
some amount of noise which of course would not be attenuated to the same
extent as the semiconductor. But then again it may be negligeable.


well, indeed it would raise the termal noise of the resistor network,
but we are talking about less than 1 mA currents and the noise from
the source will be by far superior. I was more concerned about adding
some DC to the output, I might just try building it, but I was trying
to be sure about possible implications before beeing happy with a
result :-)

Thanks
Francesco IZ8DWF

I am not sure why you would want to do this, your parts count would at
most be reduced by one resistor, you still need to have a DC blocking
capacitor somewhere. Or are you using a bias "T" that is already part of
the set up?

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P
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