Continuous Acquisition Mode for USB-5132

[gators]

Basically, we like to use USB-5132 to continuously fetch the data from two channels digitizer input (I/Q signals),
perform I^2 + Q^2 operation continuously in Labview, and then export the result in real-time to

C/C++/Matlab data format on PC for more complicated signal processing algorithms.

Is this possible? 

Thanks a lot for any feedback!!

[Aaron_W.]

Gators,

Thank you for posting on the NI Forums. The answer to your question is that this is not possible for the USB-5132 because it does not support continuous acquisition. Below is a link to a KnowledgeBase article that explains why and gives some benchmarks as to the data rates at which you can acquire. Hope this helps. 

NI USB-5132/5133 Acquisition Benchmarks

[Matt_E.]

Hi Gators,

It would also be interesting to know more details about the exact acquisition rates your application requires.  You mentioned wanting to do this all in real time and your ability to do this will depend a lot on exactly how much data you are trying to move.   As Aaron said the USB-5132 doesn't support the ability to fetch data from the board at the same time it is acquiring it so this may not be the best board for your application but this feature is supported by our PCI/PXI/PXIexpress digitizers.  Doing this type of real time processing though is not only dependent on a board supporting continuous acquisition though, you must also consider the bandwidth of the bus between the PC and digitizer as well as your machine's ability to actually use the data fast enough to prevent overflowing the memory buffers that are set up on your PC.  If you can give more details about the exact performance levels you are trying to accomplish you will be able to get better guidance from the forum.

-Matt

[gators]

Thank you, Matt and Aaron.

Our required sampling rate for 2-Channel Digitizer is at least 40MHz for each channel, 8-bits resolution.

Our work station has the following spec.

  OS: WinXP Prefessional SP3.

  CPU: Intel Xeon 3.60 GHz

  RAM: 3.00 GB 

Would you please suggest any PCI Digitizer card that support continuous acquisition mode,

and real-time processing on PC side? 

Thanks again for helping.

Best regards, 

gators. 

[Aaron_W.]

Gators,

I would recommend looking into the PCI-5114. It would be capable of acquiring at the speeds at which you need, however there are other items to consider. How long are you going to be acquiring data for? The time of acquisition will determine how you have to handle the data. You could store the data in RAM on your computer as long as there is not more data than you have available RAM. If you could give me a little more detail into what you will be doing I could give further recommendations.

[gators]

Aaron,

Our application is is to collect the brain signals from animals,

usually the recording session is longer than 1 hour. 

So I assume the RAM size is not enough to store raw data of entire session,

which then to be processed afterwards.

We'll have to process and display the data on-the-fly, and dump only the extracted information to files. 

If this is the case, are PCI-511X or PCI-510X series card able to handle the tasks?

Really appreciate your help.

Gators.

[Aaron_W. · Accepted solution]

Gators,

Any device you can find in the PCI form factor that is capable of acquiring fast enough for your application will work for you. The hardware has nothing to do with your ability to process and display data on the fly. How you write your program to acquire and process the data will be the determining factor of if you will be able to keep up with the data coming in. I would recommend looking into Producer / Consumer Loops to process the data. The PCI-5102 will not be able to acquire fast enough for your application, I would recommend the PCI-5114 or the PCI-5112 for your application. I would also recommend getting plenty of on-board memory for the card you buy since you are going to be acquiring data at a fast rate for such a long duration. 

[gators]

Thanks a lot.

I will look into the details of the cards that you recommended.

Gators. 

[psisterhen]

Since your use-case is acquiring IQ data, you may also want to consider the PXI/PCI-5142.  This digitizer is customized for IF and IQ applications.  It is a 2-channel, 100 MS/s, 14-bit digitizer- higher resolution than your specs but great for frequency domain performance.  It is capable of Onboard Signal Processing.  You can do alias-protected decimation, apply digital gain and offset, do custom FIR filtering of the data, and trigger on complex power levels (sqrt(I^2 + Q^2)).  All of the processing I just mentioned happens on-board as the data is acquired.

http://sine.ni.com/nips/cds/view/p/lang/en/nid/202656

http://sine.ni.com/nips/cds/view/p/lang/en/nid/202655

Just another option to consider.

Message Edited by psisterhen on 02-19-2009 05:50 PM

[CracKatoA]

Hello,

Nowadays is possible !!

http://digital.ni.com/public.nsf/allkb/63AFE9F8DB0F7F5586257811006E7E51

Bye!