How HSpice Measure Differential Output

[Ansonng]

acout=0

Hi all,
I would like to to measure the differential output of my amp, and I tried the following way.

vicm vicm vss 1350m
vip vip vicm dc=0 ac=0.5
vin vicm vin dc=0 ac=0.5

.op
.ac dec 2001 0.1 10G
.probe vdb(von vop) vp(von vop)

However, the value measured is always 0dB.

Could anyone tell me a proper way to do so? THANK YOU.

Anson

 

[Hughes]

Hspice measure the difference of magnitude by default. To measure the magnitude of difference, you need add a option acout=0 to the netlist.
.option acout=0