how to plot vco gain using Hspice???

[sonnyasu]

plot vco gain

Hi, I have met a problem during my project. I need to plot the vco gain but I don't have spectre analyzer. I 'm using hspice... Does anyone know how to plot the gain using hspice? I know you can use .measure to measure the frequency and plot against vctrl sweep. But how would you do the sweep wrt temperature and voltage changes? I 'm using .alter to sweep the vctrl and .temp to sweep the temperature but I don't know how to sweep the vdd voltage at the same time.. Anyone knows or do you know a better way to measure vco gain through Hspice?

Thanks so much!!

 

[Blackuni]

Hi,

i don't think u can measure freq. directly in u r tool.

wht I did was,

write a freq. meter module in verilogA(u can also google it ), connect it to your vco output. if every thing is correct , tool will give out the measured freq. and u can made this freq. as function of u vctrl, bias, temp based on your simulation step up.

sweep is normally 2D, if u r looking for 3D(vctrl, bias,temp) then use ".data"

hope this helps.

thanks,

 

[lisamoni]

hi sonnyasu
how have u plot freq vz control voltage of vco in hspice?can u please give me syntax?