The start and stop time of FFT command in Hspice

[020170]

FFT command in Hspice

I want to know the meaning of start and stop time in FFT command

example

#######################################

.FFT V(Vout) start =1u stop = 2u np =1024 format=norm FREQ=2G dc=off
.tran 1p 10u

#######################################

why we should 1u start time and 2u stop time?

How do I determine transient stop time?

I want somone who explain intuitively in detail

thanks

 

[yaxazaa]

Re: FFT command in Hspice

when you do fft, the time need has to be the number of signal period. Hope you understand now

 

[hr_rezaee]

FFT command in Hspice

hi
you must select in manner start and end of time that Tstop-Tstart=Period
regards