Harmonic distortions in an ideal sine wave

[jiangxb]

hi

i use a ideal sine source in cadence to output a sine wave, and process it in matlab to plot it's psd, as below

this is a ideal sine wave, but there are the 3rd and 5th harmonic distortion. why?

(i use hanning window. if no window, the harmonic distortion exist yet)

 

[analogy]

Re: harmonic distortion

Hi

The harmonic distortion may be related to the way you are saving cadence results.
Please give more details, how are you saving cadence data for matlab processing?

 

[Btrend]

Re: harmonic distortion

there is no HD3 , HD5 if you use ideal sine wave in MATLAB,
the result u got probably come from some numerical , or truncation process.

 

[jiangxb]

Re: harmonic distortion

hi analogy and Btrend
thank you

i have found the cause. i use ocnprint to output the data from cadence, and use the default precision, 6, so have truncation error. when i set precision 10, the result is correct.