Certain frequency doesn't show up in the waterfall plot

[tronne]

Dear fellow LabVIEW experts,

I'm in need of help regarding the waterfall plot.

I have collected some data that contain high peak frequencies at around 2000 Hz and 6000 Hz (as appeared in the power spectrum graph). When I read the data using the Read from Spreadsheet vi, the 6000 Hz frequency did not appear in the waterfall plot.

So, I tried to use two simulated sine signals at frequencies of 3000 Hz, and 8000 Hz (Sampling rate: 250K Hz, No. of sample: 16384). Both frequencies showed up in the power spectrum graph and waterfall plot. But, when I changed the 8000 Hz to 8400 Hz, it disappeared from the waterfall plot (it was still showing up in the power spectrum graph). When I changed back to 8000 Hz, it reappeared in the waterfall plot.

Does anyone know why the waterfall behave like this?..Is there any limit of what the waterfall plot can display?

I really appreciate any help.

Thanks a lot.

[James_D]

Hi Tronne,

Were you changing these values on the fly while the program was running, or between executions?

[tronne]

Hi James

I tried both, i.e. while program is running, and between executions.

Any idea why this might happen?

Thanks.

[James_D]

Can you upload a copy of the sample VI you've developed with the sine simulation?