a hspice problem of measure 3db bandwidth

[zhaoqin]

hspice print bandwidth

.meas ac freq3db find db(out) at = -3

the hspice is always display error

who knows why about it?

thanks

 

[Hughes]

bandwidth calcul hspice

Because:
1. The frequency range is always above zero, but you let HSPICE to measure the value of db(out) when frequency=-3Hz.
2. HSPICE doesn't know db(out)

Solution:

.meas ac freq3db when VDB(OUT) = - 3

 

[zhaoqin]

.measure bandwidth frequency in spice

thank you very very much
love you ^_^