PXI-4472 and NI-FGEN Express will not create sine waves at certain Frequencies

[CurtisS]

I am trying to create a sine wave at particular frequencies using the Simulate Signal Express VI and the NI-FGEN Express VI. For certain frequencies, such as 1.2 Hz, the Simulate Signal VI creates a signal with a length of 33333 samples (at 40,000 Hz signal generation with integer number of cycles on). I need an interger number of cycles due to the fact the NI- PXI 4472 card creating the signal is running more than one cycle/period. The NI_FGEN Express VI refuses to create this signal though due to the fact it will only create waveforms with a waveform length increment of 4 samples. Is there a way around this problem that anyone knows of?

[GDEV]

I'm a little confused about using the NI-PCI 4472 with the NI-FGEN (Arb) Express VI. From the coersion message it looks like you use a NI 5421 to generate the simulated signal. Try setting the number of samples manually or vary the sample rate. In order to create a signal with 1.2Hz at 40KS/s you could use 333330 samples (10 periods).

P.S. The waveform quantum of 4 samples for the NI 5421 is specified in the hardware specifications. Since this is a hardware requirement the Express VI can not ignore it.

Marian Koop

[CurtisS]

Sorry, I am using the 5421 to generate the signal and the 4472 to collect the feedback.

I ended up duplicating the samples three extra times before I sent them to the NI-FGEN(Arb) Express VI. That way it would always be divisble by four for every frequency.