problem with AC operating point analysis

* gnetlist -g spice-noqsi -o test_gyrator.net test_gyrator.sch
* SPICE file generated by spice-noqsi version 20170819
* Send requests or bug reports to [EMAIL="jpd@noqsi.com"]jpd@noqsi.com[/EMAIL]
Vtest Vtest GND dc 1
+ac 1
R1 Vtest Ltest 50      
XGYRATOR Ltest GYRATOR
.INCLUDE gyrator.net
.control
set noaskquit
AC LIN 1000 100Meg 200Meg
run
let S11=(2*v(Ltest)/v(Vtest)-1)
settype s-param S11

let S11db=db(S11)
settype decibel S11db

let P11=180*ph(s11)/pi
settype phase P11

plot s11db ylimit -0.5 0
plot P11

print S11 > S11_gyrator.log
*plot smithgrid S11
*wrs2p s3046.s2p $ write touchstone vers. 1 file s3046.s2p
.endc

* gnetlist -g spice-noqsi -o gyrator.net gyrator.sch
* SPICE file generated by spice-noqsi version 20170819
* Send requests or bug reports to [EMAIL="jpd@noqsi.com"]jpd@noqsi.com[/EMAIL]
.subckt GYRATOR X1.IN
V_IP_X1 2 1 DC 0V  
V_IP_Gm2 3 X1.IN DC 0V  
*
G2 3 GND 1 GND -20m
CL GND 1 1pF      
.ENDS

[phung@archlinux frequency_trap]$ gnetlist -g spice-noqsi gyrator.sch -o gyrator.net
reading specific gafrcLoading schematic [/home/phung/Documents/Grive/Personal/Analog/Active_Inductor/frequency_trap/gyrator.sch]
[phung@archlinux frequency_trap]$ gnetlist -g spice-noqsi test_gyrator.sch -o test_gyrator.net
reading specific gafrcLoading schematic [/home/phung/Documents/Grive/Personal/Analog/Active_Inductor/frequency_trap/test_gyrator.sch]
[phung@archlinux frequency_trap]$ ngspice test_gyrator.net

ngspice-27 : Circuit level simulation program
The U. C. Berkeley CAD Group
Copyright 1985-1994, Regents of the University of California.
Please get your ngspice manual from http://ngspice.sourceforge.net/docs.html
Please file your bug-reports at http://ngspice.sourceforge.net/bugrep.html
Creation Date: Thu Jan 25 00:28:30 +08 2018

Circuit: * gnetlist -g spice-noqsi -o test_gyrator.net test_gyrator.sch

Doing analysis at TEMP = 27.000000 and TNOM = 27.000000

Warning: singular matrix: check nodes xgyrator.1 and xgyrator.1

Note: Starting dynamic gmin stepping
Trying gmin = 1.0000E-03 Note: One successful gmin step
Trying gmin = 1.0000E-04 Note: One successful gmin step
Trying gmin = 1.0000E-05 Note: One successful gmin step
Trying gmin = 1.0000E-06 Note: One successful gmin step
Trying gmin = 1.0000E-07 Note: One successful gmin step
Trying gmin = 1.0000E-08 Note: One successful gmin step
Trying gmin = 1.0000E-09 Note: One successful gmin step
Trying gmin = 1.0000E-10 Note: One successful gmin step
Trying gmin = 1.0000E-11 Note: One successful gmin step
Trying gmin = 1.0000E-12 Note: One successful gmin step
Trying gmin = 1.0000E-12 Note: One successful gmin step
Warning: singular matrix: check nodes xgyrator.1 and xgyrator.1

Warning: Dynamic gmin stepping failed
Note: Starting source stepping
Supplies reduced to 0.0000% Warning: singular matrix: check nodes xgyrator.1 and xgyrator.1

Trying gmin = 1.0000E-02 Note: One successful gmin step
Trying gmin = 1.0000E-03 Note: One successful gmin step
Trying gmin = 1.0000E-04 Note: One successful gmin step
Trying gmin = 1.0000E-05 Note: One successful gmin step
Trying gmin = 1.0000E-06 Note: One successful gmin step
Trying gmin = 1.0000E-07 Note: One successful gmin step
Trying gmin = 1.0000E-08 Note: One successful gmin step
Trying gmin = 1.0000E-09 Note: One successful gmin step
Trying gmin = 1.0000E-10 Note: One successful gmin step
Trying gmin = 1.0000E-11 Note: One successful gmin step
Trying gmin = 1.0000E-12 Note: One successful gmin step
Note: One successful source step
Supplies reduced to 0.1000% Warning: singular matrix: check nodes xgyrator.1 and xgyrator.1

Supplies reduced to 0.0000% Warning: singular matrix: check nodes xgyrator.1 and xgyrator.1

Warning: source stepping failed

AC operating point failed -
Last Node Voltages

Node Last Voltage Previous Iter
---- ------------ -------------
vtest 0 0
ltest 0 0
xgyrator.2 0 0
xgyrator.1 0 0
xgyrator.3 0 0
v.xgyrator.v_ip_gm2#branch 0 0
v.xgyrator.v_ip_x1#branch 0 0
vtest#branch 0 0

doAnalyses: iteration limit reached

ac simulation(s) aborted
Doing analysis at TEMP = 27.000000 and TNOM = 27.000000

Error(parse.c--checkvalid): ltest: no such vector.
Error: no such vector s11.
Error(parse.c--checkvalid): s11: no such vector.
Error: no such vector s11db.
Error(parse.c--checkvalid): s11: no such vector.
Error: no such vector p11.
Error: no such vector s11db
Error: no such vector p11
Error(parse.c--checkvalid): s11: no such vector.
ngspice 956 ->

Click to expand...