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BNC (Coax) to Twisted-Pair Converter ?

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mc_eddy

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Hallo,

i'am searching for a circuit that can convert Video-signals from
BNC to Twisted pair cable and back.

Is there a selfmade circuit, or chip that can handle it ?


Greetings
mc_eddy
 

flatulent

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differential amplifiers

TI has many fully differential amplifiers http://focus.ti.com/docs/search/par...param_table&templateId=3&showAssociated=false
To convert form single ended to differential, drive just one input and ground the other. To convert to single ended, drive both inputs and take the output from just one output. make sure you present the right impedance to the lines at both ends by using resistors of the proper value, probably 70 ohms.
 

klug

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Look at aproximate circuit on LM733 - there is circuit of TV decoder, but you can realize idea.

Pin 14 - input 1 - signal
Pin 1 - input 2 - 1/2 of 5V supply.
Pin 7 - first (inverting) output.
Pin 8 - second (noninverting) output.

To use it with twisted pair you will need to add resistors to line as Flatulent has said.
 

flatulent

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first choice

I was considering suggesting this IC but it is discontinued. A slightly better version is the NE592 http://www-us.semiconductors.philips.com/acrobat/applicationnotes/AN141.pdf

http://www.semiconductors.philips.com/acrobat/datasheets/NE592.pdf

The problem with this chip is the limited output current. A buffer will be needd to drive a 70 ohm line.

Othewise, this is a wonderful IC for broad band amplifiers and I have designed it into several systems. This IC started life about 30 years ago for reading from core memory.
 

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