I'd think it might, but the AC voltmeter is measuring the average (or RMS-calibrated) signal that remains after the 1kHz tone has been removed. I suppose it only has to be attenuated by at least 12dB (probably more) so it doesn't contribute to the rest of the signal. But if the 1kHz tone level is measured at the peak, then the noise can probably be measured the same way.
Someone with both setups should do an experiment and see what the correlation is. Another test would be to go for 20dB quieting, which is easily measured, and see what the audio SA shows for the noise amplitude compared to the unsquelched noise. Bob M. ====== --- DCFluX <[EMAIL PROTECTED]> wrote: > Wouldn't the SINAD be the distance between the 1kHz > tone "Spike" and > the noise "Grass"? > > On 3/6/06, Bob Dengler > <[EMAIL PROTECTED]> wrote: > > At 3/6/2006 09:38 AM, you wrote: > > > > >Ok, I wasn't thinking in this direction before, > but I do have an audio > > >band spectrum analyzer handy. > > > > > >Question is, how can I translate this to a Sinad > measurement? > > > > I've been trying to figure this out too, as I've > been working on an audio > > spectrum analyzer program & wanted to throw in a > SINAD meter. > > > > Subsequent post from Bob M.: > > > > >With that audio spectrum analyzer, adjust it for > full > > >scale on the fundamental, and look at the noise > and > > >any harmonics. Increase the RF signal level until > this > > >drops to 25% (1/4) of the level of the 1kHz tone. > This > > >will be the 12dB SINAD point, assuming that the > > >wideband noise etc doesn't add up to more than > the > > >-12dB signal amplitude. Once you calibrate your > > >equipment with a real SINAD setup, you should be > able > > >to continue using the audio SA. > > > > So I guess I could remove the 1 kHz data from the > FFT'd spectrum, do an > > inverse FFT & ratio that result with the original > 1 kHz signal to get > > SINAD. Or maybe just add the values of all the > remaining frequency bins, > > but somehow I think that may not yield the same > result. > > > > ? > > > > Bob NO6B __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
