6722 at higher frequencies (about 3.125kHz)

[db2nc]

Hallo,

how can I control the PCI 6722 with higher frequencies about 3.125kHz? Is it possible to use Labview? How? If it is not possible, how can I control the card at higher frequencies and visualize the information in Labview? I haven't found any link for manuals etc. which help. So links are welcome.

Thanks,

Verena

[DFGray]

The PCI-6722 uses the DAQmx driver, so you can run it from LabVIEW.  Use the DAQ Wizard to quickly generate starter code, or look for examples of analog output in the LabVIEW examples.  There are many.  You can get 800kS/s output on a single channel, and sample rates must be an integral multiple of 20MHz, so you should have not trouble getting your required frequency.  Note that the output bandwidth is near 10kHz, so you may see attenuation of sharp edges in your waveforms, if they exist.  Sine wave should work well.

[db2nc]

Thanks for the response. Actually, I currently have problems with reading a digital signal. Regarding to the spec it should work, but it currently doesn't. First, I create a TTL-signal with the analog output and then read it back via digital input. When I compare the waveforms I have undersampling and input and output waveform differ.

[DFGray · Accepted solution]

The PCI-6722 does not support digital waveform input.  It's digital lines are static (unbuffered), so any waveform acquisition from them has to be software controlled.  Since modern, multitasking operating systems are not deterministic, this results in large amounts of jitter in when samples are gathered.  If you need good digital waveform input, you will need a different card.  However, the 6722 does have two counter/timers, so if the function you are trying to perform is withing their capabilities (e.g. determine frequency of an input digital waveform), you may be fine.  Let us know what task you are trying to accomplish and we can point you in the right direction.