Video inversion

[manjunathgn]

Dear All,

I hav some video data and need to invert the signal. I hav a video data -2vpp and need to invert this data to 2vpp. Can anybody suggest me some good video amplifiers which can do the job. I hav some nosie along with -2vpp and need to retain the noise and after inverting the signal

Circuit diagram also appreciated.

with regards
Manju

 

[audioguru]

If your video is composite that has sync pulses with it then you need a fairly complicated circuit so that the sync pulses are not inverted.

When pay-per-view on cable TV was analog its scrambling inverted the video sometimes (it also removed some of the sync pulses). It was fun to make a circuit that unscrambled it.

 

[manjunathgn]

Thanks For the reply,
Mine is raw video from a radar, I was trying to use AD829 from analog Devices. I was able to invert it buy feeding the ip to inverting terminal. But there is a dc shift of abt 1.0 to 1.5v.

 

[audioguru]

If your signal has a negative voltage then the output will be a positive voltage. Add an input offset voltage (through a resistor) to reduce the output offset voltage.

 

[manjunathgn]

hi,
Thanks fr reply. But i had rigged up in the same as u had sent ..but no luck. And more thing is my waveform i.e rise time is also not good.
I want circuit ver i can vary the dc offset and gain separately using different pots. Here in my circuit both gain n offset are varying ven i vary the pot connected at feedback resistor