Understanding the Symmetry setting of the SinePower waveform

[Guest]

I am trying to figure out the precise behavior of all waveforms supported by the AnalogOut instrument so I can document them. In particular, I was curious about the way the symmetry setting influences the waveforms.

Most of it I have figured out (see https://github.com/sidneycadot/pydwf/blob/master/source/pydwf-examples/analog_output_node_utilities.py), but the SinePower waveform is still a bit of a question mark. For positive values of symmetry, it transforms a regular sine function by raising it to the power (1 - symmetry / 100).

However, for the SinePower waveform only, the symmetry value is also valid in the negative range (-100..0), and I have been unable to figure out the formula used there.

If anyone could explain how the symmetry value affects the SinePower for negative symmetry values, I'd be thankful!

Best, Sidney

 

[attila]

Hi @reddish

[Guest]

Tar and feathers onto me for not checking the documentation! ? It works perfectly now.

I think that the condition as stated in the documentation's formula is reversed to the actual behavior; if (power <= 0), the exponent is (100 / (100-power)), and (if power >= 0), the exponent is ((100+power) / 100). Raising the sine to a higher power will make the sine shrink horizontally; raising it to a small positive value will make it more block-like.

I've attached a nice animated gif of the 9 regular waveforms and how they react to different symmetry settings to celebrate that I have the entire collection complete now :-)

Thanks for the pointer, much appreciated.