Integrate and Derivate Sine

[MrrM]

Hi,
I've a PXI-7841R (FPGA).
My VI needs to send the derivative of a sine wave (volts) to an external card and acquire a sine wave input (velocity) that I have to integrate. 

The sine wave later become with two harmonics.
When the frequency is too high, I notice aliasing problems and the sine's derivative  amplitude and integral are not exact.

 

Checking with simulink, for example with a sinusoid of amplitude 1, the integral should have amplitude 2 and the derivative 1.

 

I have attached a screenshot of simulink and VI simple to check if the integral and the derivative values are corrected, by changing the frequency.

 

Any help would be appreciated.

 

Regards

dev int simulate - Copia.vi

[chris754]

Integral of b*sin(ax) = -(b/a)cos(ax)+c
Derivative of b*sin(ax) = ab*sin(x)

 

In you example a=1, b=1 and c=1. They all have an amplitude of 2, but your integral is shifted up 1.

[0_o]

I didn't read the post yet the calculation caught my eye.

chris754, I guess you wanted to write in the derivative = abCos(ax)

[MrrM]

sorry

 

"......Checking with simulink, for example with a sinusoid of amplitude 1, the integral should have amplitude 1 and the derivative 1...."

 

The problem is in Labview when I change frequency the sine's derivative amplitude and integral are not exact.

[chris754]

I didn't read the post yet the calculation caught my eye.

chris754, I guess you wanted to write in the derivative = abCos(ax)

 

yes, sorry, I meant cos not sin, thank you.