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How to calculate the optimal Sinewave?


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How do we calculate the optimal Sine wave waveform on a NI-6723?

 

What is the best settings to generate a clean sine wave with the NI-6723?

According to the specs it can do 800KS/s (45KSamplings/second per channel). I'm using 8 AO channels.

What would be the best settings for the Waveform Buffer Generation and for the DAQmx Timing (Sample Clock)?

Do I need to add a Regen?

 

Other information:

 

When I set the Resulting Sample Clock Rate to 450000, the card gives no issues and generates a somewhat clean sine wave, with the exception of spikes when the sine wave crosses 0 (Glitch Energy of the NI-6723, scoping it does show it is as per specs of 2us for 400mv, this will be problematic when my lowest amplitude is 450mV...).

 

I inherited a code and need to clean up the sine waves generated by the NI-6723 at 45KS/s for 3KHz with a forced samples per buffer at 750:

gallery_17307_121_6238.png

 

When I set Sampling Rate at 450KS/s

gallery_17307_121_12209.png

 

This was the code that generated the sine wave (20 instead of 2 and the disable was enabled).

The code I inherited is at least 100 monitors square with a lot of loops and flat sequences, so I'm not sure if I can accelerate the loop (it is not running on a RT, so I assume it can be changed to a normal loop with a Wait for Next). I'm testing the code in a test vi.

gallery_17307_121_14186.png

 

Thanks

 

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Why not use a phase register (incrementing counter with rollover) and input that into a sine function?

 

Not entirely sure what you are suggesting.

 

Not sure this would be the best option, sometimes loops are late in this massive application. There's even a LED on the front panel indication the user when the loop is late... So if some loops are late, this will distort the sine wave generated in that small loop. The system is not running on RT LabVIEW.

 

This is what I get when I search for your suggestion:

http://www.edn.com/design/analog/4320590/Shift-registers-and-resistors-deliver-multiphase-sine-waves

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