Calculate Pole/Zero in hspice

Status
Not open for further replies.

seamoss

Junior Member level 3
Joined
Jun 14, 2012
Messages
26
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,453
I want to learn .PZ analysis in hspice and in order to do so I created a simple testbench for a RC circuit:
R1 A B 1k
C1 B 0 1n
Vpz A 0 DC 1 AC 1
.PZ V(B) Vpz

I expect the pole to be at 1MHz but spice gives me extremely weird results:

poles (rad/sec) poles ( hertz)
real imag real imag
-3.597314e+04 0. -5.725302e+03 0.
-1.000000e+06 0. -1.591549e+05 0.

zeros (rad/sec) zeros ( hertz)
real imag real imag
-3.597314e+04 0. -5.725302e+03 0.

***** constant factor = 1.000000e+06

First of all I dont know why I see two poles, and secondly the none of frequency (hertz) matches to 1Mhz. Did anybody try this before ?
 

The RC time constant = 1 uS.

The rolloff freq is different, 159 kHz.

Thanks for your reply, now it makes more sense. I am guessing you are taking the 2nd pole listed in the output. What about the first one which is @ -3.597314e+04 0. -5.725302e+03 0. ?
 

Status
Not open for further replies.

Similar threads

Cookies are required to use this site. You must accept them to continue using the site. Learn more…