CE Amplifier in Spice.

[Nigel Goodwin]

I have seen FFT graphs in swCAD could never interpret them. What are they for?

They show all harmonics of a signal. look at the sine-wave input signal which doesn't have any harmonics.

This is what I saw when I tried to get the FFT of a Sine wave... I expected a single peak. Or have I made a mistake...

It looks to me like your vertical scale is FAR too big, why would you want a scale that goes down to -300dB?.

I might also make my usual comment about simulators?, have you considered doing electronics rather than computer games?.

 

[lord loh.]

It looks to me like your vertical scale is FAR too big, why would you want a scale that goes down to -300dB?.

I did not se the scale... It was what appeared when I simulated...

I might also make my usual comment about simulators?, have you considered doing electronics rather than computer games?.

If I compute the fourier series of a pure sine wave I shall still get a A0 term (The DC component) and a series of sines and cosines.

Nigel, What do you suggest I do to learn the use of FFT?

 

[audioguru]

Stupid sim program and stupid me. I corrected the scales but the FFT still didn't look correct. Then I stupidly set the number of data points to max and the darn thing hyjacked my pc and it went beserk for a long time. I think it tried to use 120GB of my hard drive before I stopped it!