Arbitrary Mode in Function Generator

Dear all,

I am trying to use the arbitrary mode of the Function Generator to output a signal I generated in Matlab. I import one period of the signal from a textfile (attached) into the points section:

The period results from the equation sin(2*pi*50*t)+sin(2*pi*100*t). Thus the frequency content should be 50 and 100 Hz, which it actually is in matlab. Using this output and computing an FFT of the Output Channel AO8 after the measurement results in:

It is clearly visible that a factor 2 exists. Where does this come from?

My aim of this is to be able to use signals defined in MATLAB as outputs from dewesoft to be able to generate more sophisticated output signals than possibe in the function gen..

Additionally, is it possible to use an external signal that is non-periodic as an output from Dewesoft that is defined as time/amplitude vectors? Or is there another way to use externally defined signals and output those through dewesoft to i.e. an amplifier/shaker?

Any feedback is highly appreciated.

Thanks in advance and best regards,

Parick

Dear Patrick,

when you are defining the Arbitrary points, you need to take into account that you are inserting the point for one period. The period is defined in the FG settings with the Frequency value. In your case you had the Frequency value set to 100Hz as in the following picture:

So in your case you can set this to 50Hz, which would represent the slower frequency and you will get the proper result.

You can also create a formula with the same equation:

 sin(2*pi*50*time)+sin(2*pi*100*time)

And then assign it to the AO

In that way you can use any channel for the AO.

If you will need an additional help please let us know.

Best Regards,

Thank you, Eva. This has been very useful information.

Best regards,

Patrick