[EE] 24-bit A/D. Are We in the Twilite Zone Here?
Andrew Kunz email (remove spam text)
WOW, now that makes sense.
The signal was FM/FSK on a TV cable, with our carrier too close to Channel 2.
The "standard" was a SAM-II meter which measures signal level in dBmV. Standard
equipment for cable TV.
The goal was averaged signal level, not instantaneous.
Glad somebody knew what I was talking about - I sure don't!
"Peter L. Peres" <ACTCOM.CO.IL> on 05/04/2000 06:46:38 PM plp
Please respond to pic microcontroller discussion list <MITVMA.MIT.EDU> PICLIST
cc: (bcc: Andrew Kunz/TDI_NOTES)
Subject: Re: [OT] [EE] 24-bit A/D. Are We in the Twilite
wrt. Andy Kunz's adding digital noise: I think that I know what is on.
He said that he has a very poor S/N at the input. I infer that he tried to
obtain a steady readout of the average RF level measured while receiving
modulated (AM ? - he does not say) rf signals. For this, he needed to
smooth the input somehow, to obtain something resembling RMS. By adding
'fast' noise I think that he faked oversampling, and then averaged the
result. This would be a median filter, done otherwise, imho. He also said,
that 'the result was surprisingly accurate' which means that he was
measuring the same signal also using other means, which means for RF are
either a specan or a rf milivolt/miliwattmeter. All three devices read out
RMS integrated over some time unless set up otherwise (i.e. peak or
instant power etc).
am I way off ?
See also: www.piclist.com/techref/io/atod.htm?key=a%2Fd
You must be a member of the
piclist mailing list
(not only a www.piclist.com member) to post to the