Posted by Richard Crowley on 01/10/55 11:43

"William Davis" wrote ...
> Rick Merrill wrote:
>
>> Richard Crowley wrote:
>> > "Rick Merrill" wrote ...
>> >
>> >> Richard Crowley wrote:
>> >>
>> >>> "soundwhiz" wrote ...
>> >>>
>> >>>> the best possible option is to use a audio mixer to defaet
>> >>>> the function
>> >>>
>> >>>
>> >>>
>> >>> It is not possible to defeat the AGC with a mixer or any other
>> >>> kind of external device or scheme.
>> >>
>> >>
>> >> Ok, what about the following Rube-Goldberg scheme: the camcorder
>> >> has a stereo input, so put a BIG sound on the right channel and
>> >> record the target (mono) on the left channel. Then in playback
>> >> cast out (ignore) the right channel??????????!!!!!!!!!!!!!
>> >
>> >
>> > You are not defeating the AGC, you are only trying to
>> > "trick" it. Good luck. I wouldn't have any expectations
>> > that this will work. Certainly not enough to waste anyone
>> > elses' time fooling around trying to use it. But to each his own.
>>
>> As I recall Troy was "tricked" and defeated. Wish me luck.
>
> Another possibility would be to feed a low frequency "pilot" tone into
> the recording at a frequency that you can notch out later.
>
> The AGC should see the tone as a consistent level, and that
> should keep the AGC from pumping.

Well, the AGC will react to the SUM of the "pilot tone" and the
program material. A thought flashed through my decrepit brain
that you could modulate the pilot tone (downward) with the
envelope of the program material and even tune it to exactly
counteract the AGC circuit parameters (attack & decay time,
compression ratio, etc). Distasteful and even Rube Goldberg-
like (Heath Robinson to readers in the UK), but it has some
possibility of working. (If the audio chain doesn't produce any
harmonics of your "pilot tone", that is. :-)

[Back to original message]