how to control the time step in .Tran analysis in spice3?

Hello, everyone,

I am doing some simulation of VCO (4 stage differential) in spice3. When I do the .tran analysis, the time interval of the output is not uniformly distributed. It is not the time step I gave in the command: ..tran Tstep Tstop.

In my work, I need the timestep to be uniformly distributed. How can I control it?

Thanks!

Reply to
cici
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use the 'linearize' command:

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Also, note the comments about not setting Tmax in

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Charles.

Reply to
Charles DH Williams

That will certainly work, although if the samples are intended for use with an FFT, the linear interpolation will introduce enough error that the noise floor will be rather high -- like -90db from the signal, at best...

--Steve

Reply to
Steve

Thanks for your reply. I tried the command "linearize", it does work when I type the command in spice3 invironment. However, when I put the all the commands into one spice file, it does not work. I was using :

.tran .. .. .linearize V(1) .print tran V(1)

The result is still as there is no ".linearize" command. How can I solve this problem? Thanks!

cici

Reply to
cici

Linearize is a spice3 interactive command. There is no dot-command equivalent so you need to replace the above lines by:

..tran .. .. ..control run linearize v(1) print tran.v(1) ..endc

Charles

Reply to
Charles DH Williams

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