As the original post mentioned a service monitor and a
Micor repeater, I just "assumed" that it was the
repeater's deviation that he was interested in.
Touch-tones are a complex signal formed by two
unrelated audio tones. There's also some inequality in
the levels of the two tones as well as purity of the
signals that will get modified if the level is too
high. The 3-4 kHz deviation on touch-tones is
apppropriate for a mobile or hand-held radio.
The deviation can be measured with a meter or a scope
only if you're using a constant sine wave as the input
signal. Once you start looking at complex waveforms or
voice, you must use a scope to set the absolute peaks.
The meter will read lower under such conditions.
The choice of using 400 Hz or 1 kHz is more of a
matter of convenience, however the transmitter's
pre-emphasis will have a bit more effect on the 1 kHz
tone, so you might need less audio for a given amount
of deviation.
Bob M.
======
--- mch <[EMAIL PROTECTED]> wrote:
> TT should be between 3 and 4 kHz deviation.
> (preferably closer to 3)
>
> Joe M.
>
> Charles Greene wrote:
> >
> > Ken,
> >
> > Shouldn't the touch tone pad tone be set at the
> maximum deviation or
> > nearly so? Those are steady and not subject to
> peaks. Also I take
> > it the max deviation should be set with a 1Khz
> audio tone applied>
> >
> > 73, Chas W1CG
> >
> > At 05:05 PM 12/2/2005, you wrote:
> > >One thing that hasn't been mentioned so far, and
> one thing that is quite
> > >important, is that regardless of the suggestion
> of 5 or 4.75 Khz, it must
> > >be noted that these are PEAK values, not average.
> > >
> > >If the average deviation is set for 5 KHz, then
> the peaks will be
> > >absolutely be more than 5 Khz.
> > >
> > >So use the scope in the service monitor, not the
> meter
> > >
> > >Ken
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