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Add S-parameter support for Ngspice #84
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HI to all S-parameter users. Prof Jont Allen (jontallen@ieee.org, auditorymodels.org) |
There is an update to RF for ngspice available at a new ngspice git branch s-parameters-2. An update to the manual is still needed. Do you have some circuit examples for me to add to the ngspice examples distribution? Holger |
I have just made an update to the ngspice manual (chapters 4.1.11, 15.3.8, and 17.5.80), see http://ngspice.sourceforge.net/docs.html. |
Hello Holger, |
Examples added by c4c6252 |
Hello Tom, |
Any update on the 0.0.24 version? |
Hello Tom, currently two tasks are remaining for 0.0.24:
The Ngspice version from the latest git cannot process the default Qucs |
Vadim Will the "RF" components in Qucs 0.0.20 be enabled in the next version of Qucs-S? Most seem to be in the source for Qucs-S. Transmission lines like microstrip and coplanar elements? RF Components including the "new" Inductor and Capacitor with "Q"? |
Hello Tom, |
The S-parameter simulation with Ngspice>=37 become available in the 0.0.24 release (published on July, 01). The simulation of the active and passive circuits containing lumped device is currently implemented. The implementation of the microstrip devices model will be considered as the separate task for the next releases. |
Vadim I tried to display S-parameters in dB like in Qucs but no luck. Since there are no errors I cannot figure out what's wrong. |
@tomhajjar You need to use Nutmeg equations with Ngspice (Spice specific sections->Nutmeg equation). The Qucs equations may have no effect and kept for backward compatibility. Also you need to select a simulation related to this equation in its properties. Since 0.0.24 the Qucs-S will insert Nutmeg equation on schematic by default if the Ngspice is selected as the simulation engine. |
I got it working. The group_delay function in ngspice has issues. The plot has large discontinuities in-band as seen in the 3plpf circuit. The group delay function in Qucs 0.0.20 works better. |
@tomhajjar Yes, it seems the group_delay function in Ngspice has the wrong implementation. A bug report should be submitted to Ngspice mailing lists. |
Holger Vogt over at the sourceforge ngspice discussion came up with a workaround. ngspice will be fixed in a future release. Group_Delay = -1*deriv(cph(S_2_1))/2/pi |
Related to #79 S-parameter simulation
.SP
will be added in Ngspice-37. Currently it is available from Ngspice Git. It's need to implement it in the Qucs-S. The following tasks need to be done:Provide equivalent for Qucs stoz() and stoy() functions, because currently Ngspice can output only S-matrixThe latest Ngspice version outputs Y and Z matrix, not need to implement postprocessor functionsThe text was updated successfully, but these errors were encountered: