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Posted by Smarty on 10/06/05 21:22
Most if not all of the camcorders do AGC on the audio inputs, and have at
least 60 to 80 dB of dynamic range. Virtually all the camcorders use
unbalanced inputs. I have build T-pad attenuators with a simple 3-resistor
T-network to do precisely what the original post asked for, and the
attenuators which do around 30 or so dB seem to work just fine. Putting in
too much attenuation forces the AGC to "gain-up" and crushes the SNR by
raising the noise floor.
Smarty
"Larry J." <usenet2@DE.LETE.THISljvideo.com> wrote in message
news:Xns96E78BC2755B6thefrogprince@68.6.19.6...
> Waiving the right to remain silent, "Smarty" <nobody@nobody.com>
> said:
>
>> You will not need equalization, but you do need to attenuate the
>> line level signal (nominally about 1 millivolt into 47K ohms)
>> down to a few microvolts (also at the same impedance). Thus an
>> attenuator / pad of about 30 dB should do it.
>
> An even larger pad could be required. Unbalanced live levels are
> generally -10 to -20db. Balanced can be as high as +8.
>
> --
> Larry Jandro
> Video Engineering & Equipment Rentals
> Scottsdale, Arizona, USA
> [Remove spamtrap in ALLCAPS to reply]
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