[BC] Audio "proofs"

[Harold Hallikainen]

> One huge issue is spurious emission stability under various tune, load and
> power levels.  FM PA can exhibit strange issues a they run into different
> operating points and loads.  Its almost a re-cert. in field.  By the way
> when some one says proof are they saying RF spuri vs. the old audio proof?
>  Can't see any specs. today for an audio proof.
>
> Warren Shulz
> WLS CGO

True, there are no specifications for audio anymore. I don't even see a
specification for preemphasis other than the graph at
http://www.hallikainen.org/FCC/FccRules/2009/73/333/section.pdf . Of
course, there used to be specifications for frequency response, THD,
noise, stereo separation, and stereo crosstalk (L+R to L-R and the
reverse). The FCC decided that market pressures would pressure stations to
have good audio. However, without a basic standard such as preemphasis,
there is no "bright line perfection" to shoot for.

On the term "proof", I believe the old audio measurements were indeed
called "proof of performance" measurements. The new RF tests are
"equipment performance measurements" (see
http://www.hallikainen.com/FccRules/2011/73/1590/ ).

Harold