USB 8451 waveform generator

[R_J]

Hi,

Can we generate a square waveform by using digital I/O lines of USB 8451 card ?

[JK1]

This is a good example for generating the wavform using digital lines.

C:\Program Files\National Instruments\LabVIEW 8.6\examples\DAQmx\Digital\Generate Values.llb\Write Dig Chan-Ext Clk.vi

Also just make a small computation on the maximum frequency you can generate with this hardware and it is within the limits that you require

[R_J]

HI,

Thanxs for your kind reply. I do not have DAQ drivers installed in my PC. I want to generate a waveform of freq 1.25 MHz.  the time between two high is 800 ns with width of high is 80 nsec.

[R_J]

Is there any buffer available on the 8451 card for waveform generation ?

[AdnanZ]

Correct me if I am wrong, but what I believe you want to do is to generate a pulse train. If so, you need counters on the card. The USB 8451 does not offer counter/timer functionality; it has a built-in SPI/I2C interfaces. Since you can only use static (i.e. software timed) digital I/Os on the 8451, you could generate software-timed pulses. But, the jitter (timing deviation) could be a huge problem and I wouldn't recommend going down that path. For generating pulse trains I would recommend a basic E or M series DAQmx device.

[JK1]

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I want to generate a waveform of freq 1.25 MHz.  the time between two high is 800 ns with width of high is 80 nsec.

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Generating pulse train of this high frequency and precise duty cycle is not recommended using this card.  Such high frequency can be generated using counter provided by E or M series card that provides STC.  Software timed pulse generation that you are trying to establish are suitable only for low frequencies where jitter is not of much concern.

Post back for queries

[R_J]

Hi,

Thanks for the reply. I have one doubt.

While selecting card for such type for waveform generation what all parameters i should keep in mind like buffer on board, Timebase etc.

& how much frequeny signal we can generate with Digital I/O (E & M series DAQ card)

Regards,

J