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Video amplifier question

(Richard) #1

My cctv system clearly needs some amplification for improved picture quality. I am looking at using the NTE927 differential video amplifier (http://www.nteinc.com/specs/900to999/pdf/nte927.pdf). I am uncertain as to the proper way to wire it into my system. I would appreciate some help. I have been unable to find answers searching the internet.

Can I apply 12 volts across V(+) and V(-) for power, or do I need some kind of balanced voltage input for power? For video input can I apply the output from the camera across the 927 input connection, or do I need some kind of balanced input? Can I feed the output directly to the cat5e twisted pair?



(Rusty) #2

Hi Richard,

That video amplifier requires differential input, which you won’t get from a standard camera. You also need a dual supply power supply to supply a maximum of +/- 8 volts.

I’m guessing you want to supply +12V to the positive input and 0V to the negative input? That would work, however, you would need a video signal that is grounded around 6V, which you won’t get from the camera. You would also need the receiving end to bump that voltage back down to 0V-biased.

Here’s an excellent differential video amplifier circuit you can use: http://www.ti.com/lit/an/snoa422c/snoa422c.pdf

Unfortunately this one requires quite a bit of external hardware including a -5V supply.

Best regards,