/**
\page tune_page TUNE - Transmit a single tone carrier.

\tableofcontents

\section tune TUNE Mode

Too often you see an overdriven signals on the digital sub-bands;
multiple audio sidebands on PSK, splatter from overdriven MFSK and
RTTY. There is absolutely no reason for a transceiver driven
by fldigi to exhibit this type of performance. You can set up
your computer / transceiver for good solid performance without excessive
drive.
<br>

The "TUNE" button generates a continuous single frequency audio signal
at the exact frequency to which the waterfall cursor has been set. The peak
amplitude of this signal is the peak amplitude of every modem signal
generated by fldigi. None will exceed this value, even the simultaneous
multi-tone modes like Throb. Every modern SSB transmitter uses some automatic
level control ALC for preventing overdrive for SSB voice. A little overdrive
on a voice channel can be tolerated to a degree. In fact, that is what
an analog RF compressor does, overdrive and then subsequent filtering.
But you absolutely cannot tolerate that with the digital modes. Here is the
way to set up your transceiver for a clean signal. I recommend starting out
with a dummy load, but an "off hour" for a band might work just as well if
you do not have a dummy load.
<br>

<ul>
	<li>For Windows users</li>
	<ul>
		<li>Set your sound card output level to the minimum on the Windows
			mixer</li>
	</ul>
	<li>For Linux users</li>
	<ul>
		<li>Set your PCM level to about 80%</li>
		<li>Set your Transmit Level control for minimum output level.</li>
	</ul>
	<li>Enable the "Tune" mode in fldigi ... you do have CAT or PTT set up ...right?</li>
	<li>Make sure your transceiver's speech compression control is OFF</li>
	<li>Slowly bring up the Mixer audio out until your rig's ALC just starts
		to function (a light blinking or a meter showing this condition).</li>
	<li>Reduce the Mixer audio output until the ALC is disabled.</li>
	<li>You are now transmitting at maximum output power without distortion.</li>
</ul>

You can use any level below this and be assured that your output signal
will be clean. All digital signals that fldigi generates will be limited to
this peak-to-peak voltage. You should always use the minimum power necessary
to maintain good comms, remember that even if you are clean at 100 W you
signal will be so strong among the QRP signals that it will overpower the
AGC on many receivers that are working another digital station within the
same SSB bandwidth that you are on. You will appreciate this the first
time that you are working a weak PSK DX station and someone blasts through
and captures your AGC.
<br>

You should try the the above adjustments at different audio
frequencies. Transceivers that achieve the SSB filtering with crystal or
mechanical filters will have a considerable amount of variation across the
passband of the filter. This will show up as a varying amount of ALC that is
dependent on the audio frequency. Once you are comfortable with the process
you can very quickly repeat the "Tune" and set the power for the frequency
to which the waterfall is set.
<br>

\ref tune_page "Return to Top of Page"
<br>
\ref main_page "Return to Main Page"


*/
