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rate then is accelerated considerably for a few milliseconds, to facilitate rapid acquisition of the
optimum gain setting when a program first appears.
As mentioned earlier, adaptive-slope control preserves most of the dynamic range by slowly
increasing the gain, and only by a factor of 2 (dB) when the level drops below normal.
However, if the input level rises above normal, the gain is decreased by a considerably greater
factor, such that over-modulation is held to only a few dB even with an input greater than 20
dB above normal.
For a table of the input-output level relationship, see the specifications section of this manual.
Note that 0 dB (0 VU on the AGC's LED bar) is the nominal match-level. That is the point at
which a steady-state single tone level is unaffected when switching to or from Off / Setup and
Run modes.
The difference between stereo and double-mono modes is slight, but significant. In the
double-mono mode, the levels of the two channels are totally independent. However, in the
stereo mode, both the left and the right channels have an effect on the output level of both
channels; in general, the louder channel takes control and adjusts the gain accordingly, and
the gain of the other channel tracks it to maintain good stereo imaging.
The MODE LED on the front panel provides an indication of the status of the AGC-100:
If the MODE LED is not illuminated at all, power is not applied to the AGC-100.
If the MODE LED is fully illuminated, the AGC is in its active mode, with normal program level
present within the last ten seconds. The OFF/SETUP / ON switch must be in the ON position
for this to occur.
If the MODE LED is dimly illuminated, either of two conditions may exist, depending on the
setting of the OFF/SETUP / ON switch: If in OFF/SETUP, that is it. However, if in dim when in
the ON position, the AGC has exceeded the 10-second gain-hold period at a program pause,
and proceeded to the Setup gain setting, from which it will automatically return to the active
mode when the program returns.
28 Aug 2004
AGC-100
page 9 of 11
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