TTL Digital Output with 50 Om

[Vasilich2004]

Hi,

Is any Multifunction DAQ (USB, PCI, and PCI-e card formats) with Digital Output that work on 50 Om input? It can be Counter Output also.

Thanks,

[AnalogKid2DigitalMan]

That does not ring a bell with me, I could be wrong. Google TTL Line driver. There are off-the-shelf versions available, such as this:

http://www.pulseresearchlab.com/products/linedrivers/prl-444/prl-444_main.htm

Texas Instruments also make an IC, SN74128 logic gate (there are others too) to do such:

http://pdf1.alldatasheet.com/datasheet-pdf/view/27364/TI/74128.html

Hopefully NI will chime in with some input, no time for me to search.

-AK2DM

[Vasilich2004]

Thank you - AnalogKid.

I know both solutions but I try to avoid additional equipment. A system will have NI Multifunction card (USB is preferable, also PCI ot PCI-e). Another mechanical standard in the system is NIM.

[Aaron_W.]

Vasilich,

Thank you for posting on the NI Forums. You will want to look into our HSDIO cards. The 6535/6/7 cards would have the output impedance that you are looking for as they are all 50 ohm. You could also look at the 654X devices or the 655X devices. All of these devices are 50 ohm but are higher speed devices. What speeds of digital input/output are you looking for? 

[Vasilich2004]

Aaron

Thank you.

My system doesn't have strong requirements. Let say 1 us delay is Ok for this signal.

But I do would like to have Multifunction DAQ.

[Aaron_W. · Accepted solution]

Vasilich,

The only digital output devices we have with a 50 ohm output impedance are our HSDIO devices. If the reason you would like a Multifunction DAQ is to use the DAQmx Driver, then the 6535/6/7 devices would be best as they use the DAQmx driver. With this said if you are not going at higher speeds with your Digital Output you may be able to get away with using a DAQ device with an output impedance higher than 50 ohms. If it is absolutely necessary that you use a device with 50 ohm output impedance then the HSDIO devices is the only option. Hope this helps. 

[Aaron_W.]

Vasilich,

I would like to clarify that not ALL of our High Speed Digital I/O Devices are 50 ohm output impedance the 6535/6/7 do have a 50 ohm output impedance, but I would always double check the Detailed Specifications of the device you are interested in to make sure that the output impedance is indeed 50 ohms.