On Thu, 13 Sep 2001, Dmitry Alexeyev wrote: > Hello. > > I have BT878 card and external multiplexer with several monochrome cameras > connected to it. If one camera is off ( blank screen ), bt878 > automaticaly increases brightness, so I can see nothing on frames from > other cameras. > How can i turn off AGC ? > > Dmitry > Seems your problem is the multiplexer not the AGC. If properly clamped to black level AGC will probably no longer interfere. This of course requires minimum expertise to clamp the multiplexer input to black level when camera is off (using a capacitor, resistor or combination, after analysing the input circuit). However, if you have such ability it must be pretty simple and "safe" once it's just a simple clamping. (clamping activation via camera power) But with today VLSI "closed source" trend things simple like this may even be impossible. :-( Open source hardware too will be great.... schematics, information access... or better put the closed hard crap in trash together with the closed source soft too. ;) No need to mess the AGC that seems to be not the cause but just the symptom of a floating input signal. Hope this helps. -- HOM: http://www.momentus.com.br/users/hook/ GPG: http://www.momentus.com.br/users/hook/GPG-PauloCastro.asc
