It is the ratio of (Signal + Noise+Distortion) to (Noise+Distortion) as
measured at the receiver audio output. It is measured using an RMS-reading
AC voltmeter , typically with a 1Khz modulation tone on the signal applied
to the receiver under test.

First you measure the audio signal out of the receiver using the AC RMS
meter. Then you apply a notch filter at the modulation frequency and measure
the residual noise+distortion, again using the RMS AC voltmeter. SINAD is
the ratio of the two measurements.

Joe
W3JDR



"crb" wrote in message ...
Is it only valid for AM and FM measurements?

I know its receiver sensitivity.

Is it Signal divided by Noise with distortion??

12 dB SINAD means what? The signal is 12 dB greater than noise and
distortion or
is it more complicated than that?