Hi Friends,

I am design a boot strapped switch and trying to measure distortion by looking at the DFT.

My input is 3 MHz sinusoid and the sampling clock is 20 MHz.

When i do dft of input, i expect only single tone. However to my surprise i find multiple tones.

Can any one please comment on this? Please suggest a solution on how to take a proper DFT.

Regards
Nandish

hi aaron,

I am not sure how to use .pss analysis for calculating the distortion of a boot strap switch.

My simulations setting information is as below:

1) Input is from ideal sinusiodal voltage source with 3 MHz freq.
2) Sampling frequency for sample and hold is 20 MHz
3) Simulation is ran for 10us
4) 1024 point DFT is calculated with rectangular window

I have came to know that the error i am facing is called spectral leakage. I am not sure how to manage it. I tried changing the spectral window but it didn't work.

Please suggest me some solution if you know.

Thanks for your response.

Regards
Nandish

Thanks for the link Frank.