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Examples: nport instance and command 'sp' are not compatible. 

files.cir uses sp, the others the given 137mhz_bpf.s2p
This commit is contained in:
Holger Vogt 2026-08-02 15:44:44 +02:00
parent 38a33e25d6
commit 2d6ca92a7e
3 changed files with 13 additions and 35 deletions
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12
examples/sp/file.cir
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@ -30,14 +30,6 @@ ri net1 sin 50
X1 sin sp_model_out 0 s2p_generic touchstone="137MHz_BPF.s2p"
ro sp_model_out 0 50
* A version derived from extracted s-parameters using the nport
VP4 net2 0 dc 0 ac 0.316228 ; Same as VP1 but that must not be loaded.
ri2 net2 sin2 50
N1 sin2 np_model_out 0 mymodel
.model mymodel nport(file="new_137MHz_BPF.nport")
ro2 np_model_out 0 50
* Control section, run simulations.
.control
@ -55,8 +47,8 @@ alter vp2 ac = 0
AC LIN 71 107MEG 167MEG
set xbrushwidth=2
display
plot group_delay(filter_out) sp1.Group_Delay group_delay(sp_model_out) group_delay(np_model_out)
plot db(filter_out) cph(filter_out) db(sp_model_out) cph(sp_model_out) db(np_model_out) cph(np_model_out)
plot group_delay(filter_out) sp1.Group_Delay group_delay(sp_model_out)
plot db(filter_out) cph(filter_out) db(sp_model_out) cph(sp_model_out)
.endc
* Subcircuit for SP behavioral device

10
examples/sp/file_nport.cir
View File

@ -25,7 +25,7 @@ L1 0 _net2 66N
VP4 net2 0 dc 0 ac 0.316228 ; Same as VP1 but that must not be loaded.
ri2 net2 sin2 50
N1 sin2 np_model_out 0 mymodel
.model mymodel nport(file="new_137MHz_BPF.nport")
.model mymodel nport(file="137mhz_bpf.nport")
ro2 np_model_out 0 50
* Control section, run simulations.
@ -34,10 +34,10 @@ ro2 np_model_out 0 50
* Run an SP analysis, derive group delay, write a Touchstone file
* Use this Touchstone file for vector fitting by pre_snp, thus get a file
* new_137MHz_BPF.nport
SP LIN 71 107MEG 167MEG
let Group_Delay = -1*deriv(cph(S_2_1))/(2*pi)
wrs2p new_137MHz_BPF.s2p
pre_snp -native new_137MHz_BPF.s2p
*SP LIN 71 107MEG 167MEG
*let Group_Delay = -1*deriv(cph(S_2_1))/(2*pi)
*wrs2p $inputdir/new_137mhz_bpf.s2p
pre_snp -native $inputdir/137mhz_bpf.s2p
* Now run AC analysis

26
examples/sp/file_nport_tran.cir
View File

@ -1,24 +1,13 @@
Example circuit to read a Touchstone-format parameter file.
* This file contains an an analog filter circuit; SP is run
* and the S-parameters are saved in a file.
* It then uses vector fitting for a *.nport file, serving the nport instance
* This file contains an an analog filter circuit.
* It reads a previously created Touchstone file 137mhz_bpf.s2p
* Then uses vector fitting for a *.nport file, serving the nport instance
* in a circuit that reproduces the original from its saved S-parameters.
* Results from the two versions are plotted together for comparison.
* Derived from: Qucs 1.0.2 C:/Users/Tom Hajjar/.qucs - S/S-parameter_files_ngspice_prj/137MHz_BPF.sch
* Original circuit for SP analysis
VP2 filter_out 0 dc 0 ac 0.316228 SIN(0 0.316228 136MEG) portnum 2 z0 50
VP1 _net1 0 dc 0 ac 0.316228 SIN(0 0.316228 136MEG) portnum 1 z0 50
C1 _net2 _net1 4.7P
C5 _net3 filter_out 4.7P
C3 _net3 _net2 1P
C4 _net3 0 15P
C2 0 _net2 15P
L2 0 _net3 66N
L1 0 _net2 66N
* input for both filters
VP11 in 0 dc 0 SIN(0 0.316228 136MEG)
@ -36,17 +25,14 @@ R12 filter_out1 0 50
* A version fitted from the extracted s-parameters using the nport device
ri2 in sin2 50
N1 sin2 np_model_out 0 mymodel
.model mymodel nport(file="new_137MHz_BPF.nport")
.model mymodel nport(file="137mhz_bpf.nport")
ro2 np_model_out 0 50
* Control section, run simulations.
.control
* Run an SP analysis, derive group delay, write a Touchstone file
* Use this Touchstone file for vector fitting by pre_snp, thus get a file
* Use given Touchstone file for vector fitting by pre_snp, thus get a file
* new_137MHz_BPF.nport
SP LIN 71 107MEG 167MEG ; extract S parameters
wrs2p new_137MHz_BPF.s2p ; write S parameters
pre_snp -native new_137MHz_BPF.s2p ; read S parameters, fit, create new_137MHz_BPF.nport
pre_snp -native $inputdir/137mhz_bpf.s2p ; read S parameters, fit, create new_137MHz_BPF.nport
tran 0.1n 1u
set xbrushwidth=3