"Fred McKenzie" wrote in message
...
In article , crb wrote:


Years ago sensitivity might have been measured using a "20 dB quieting"
method. You would inject an unmodulated carrier and increase its level
until the noise output of the receiver decreased to one tenth of the
no-signal value. [...snip...]

Isn't SINAD an acronym for "Signal In the presence of Noise And
Distortion"? I don't fully understand how it works, but assume there is a
1 KHz filter feeding one channel that is compared to an un-filtered
channel.
What I want to know is how to build one. Does anyone know of any SINAD
construction articles?
73, Fred, K4DII

I for got about the 20 dBQ method. That's another reference for
sensitivity on FM receivers.

That's right Fred. It's explained up thread, but basically it is the ratio
of the un-notched audio to the notched audio. The "audio" is the result a
1kHz FM modulation at 60% of rated system deviation. Originally, for 5kc
ssytems dev., the 3kc deviation was 3.3kc. WHY is this at around 2/3
maximum? Well, in a well designed Tx, the deviation will get up to this
level before the deviation limiting clipper starts to clip and cause
distortion.

73, Steve

73, Steve, K,9.D;C'I