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
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