USB Counter with 50 Ohm output

[Vasilich2004]

Hi,

A part of the system accepts TTL trigger and generates 2 pulse trains which are connected to 50 Ohm inputs. It there USB module (due laptop) which handle 50 Ohm?

Thanks, Andrey.

[dmysliwiec13]

Hello Andrey, 

Could you give me an explanation of your system setup? I am not sure what you mean by "handle 50 ohm", because resistance is usually not an issue. Is there a current limit that you are referring to?

Best, 

Danielle

[Vasilich2004]

Yes, it is current limit. Input impedances are 50 Ohm. So TTL output should have 100 mA current.

I can add line driver (one chip) but try to avoid that.

[dmysliwiec13]

Are you asking if there is a USB device that can handle an input of 100mA od current from your TTL output? If so, the answer is yes there are many USB devices that could handle this. 

Danielle

[Vasilich2004]

omg )))

I ask about ni usb counter which output can handle 100 mA to be connected to device with 50 Ohm impedance.

[dmysliwiec13]

Once again, yes there are many NI USB devices that can do this. 

[Vasilich2004]

please, provide type!

[Henrik_Volkers]

I bet you mix something 😄

If you have a 50 Ohm input , want to use a 50Ohm impedance cable and  a source with 50 ohm source impedance to avoid reflections, you would need a source with 10V 100mA output to get 5V at the input.

I have rarely seen/used such things, however triggers/signaling without reflections is done for ages without problems 🙂

So if you can give some detailed information about what you want need to do, we migth be able to give some hints 😉

[Vasilich2004]

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@Henrik_Volkers wrote:

I bet you mix something 😄

If you have a 50 Ohm input , want to use a 50Ohm impedance cable and  a source with 50 ohm source impedance to avoid reflections, you would need a source with 10V 100mA output to get 5V at the input.

I have rarely seen/used such things, however triggers/signaling without reflections is done for ages without problems 🙂

So if you can give some detailed information about what you want need to do, we migth be able to give some hints 😉

 That is incorrect approach at all!.

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[dmysliwiec13]

Henrik is correct, if you could provide a little more information about your application we can both give you better suggestions on which hardware to use. The more information the better!