Created attachment 1259990 [details] Simulation file Description of problem: Version-Release number of selected component (if applicable): How reproducible: Steps to Reproduce: 1. 2. 3. Actual results: Expected results: Additional info:
Created attachment 1259991 [details] bad simulation results
Created attachment 1259992 [details] Expected simulation results
Created attachment 1259993 [details] Circuit schematic
Sorry I attached file before filling the bug description, it was a mistake. Here is the description. * Bug description ngspice version shipped with fedora fails to simulate a simple transmission line circuit. The simulation is performed without errors but the results are wrong. It worth noting that the same simulation file gives satisfactory results with ngspice shipped with Archlinux or opensuse on differents machines. On the same machine ngspice compliled from source with default options also gives good results. * Test circuit description : The scheme is provided is the attached file myspice.ps. The test circuit is a simple 50 Ohm impedance line driven by a pulse source with an 8 Ohm impedance. The line is terminated with a 40 kOhm load. vin is the node before the transmission line, vout is the node between the end of the connection line and the load. See attached myspice.cir simulation file for netlist and simulation parameter. * Reproducing the bug Run the following command: $ ngspice myspice.cir It's always reproducible. ** Results Since the impedance matching between the load, the source and the transmission line is poor. The pulse seen by the load is expected to be distorted by multiple reflections at the end of the transmission line. The attached goodsimu.ps file shows this effect, it's obtained using my own compiled version of ngspice. The attached file badSimu.ps shows the results computed using ngspice shipped with fedora. vin is correct but vout is always 0V and no characteristic ringing is present. * My system : Fedora 25 x86_64 kernel : 4.9.7-201.fc25.x86_64 * ngspice shipped with fedora : ****** ** ngspice-26 : 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: Sun Jul 3 05:32:02 UTC 2016 ****** * My own compiled version : ****** ** ngspice-26 : 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: Sat Mar 4 14:10:16 CST 2017 ****** For compiling I did not use any special options: I just downloaded the last tarball available at sourceforge (https://sourceforge.net/projects/ngspice/files/ng-spice-rework/26/) and compiled it using ./configure followed by make.
*** Bug 844100 has been marked as a duplicate of this bug. ***
ngspice-26-8.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2017-682cd9d476
ngspice-26-8.fc25 has been submitted as an update to Fedora 25. https://bodhi.fedoraproject.org/updates/FEDORA-2017-10f4ed1314
ngspice-26-8.fc24 has been submitted as an update to Fedora 24. https://bodhi.fedoraproject.org/updates/FEDORA-2017-2b71902776
ngspice-26-8.fc26 has been pushed to the Fedora 26 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2017-682cd9d476
ngspice-26-8.fc24 has been pushed to the Fedora 24 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2017-2b71902776
ngspice-26-8.fc25 has been pushed to the Fedora 25 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2017-10f4ed1314
ngspice-26-8.fc26 has been pushed to the Fedora 26 stable repository. If problems still persist, please make note of it in this bug report.
ngspice-26-8.fc25 has been pushed to the Fedora 25 stable repository. If problems still persist, please make note of it in this bug report.
ngspice-26-8.fc24 has been pushed to the Fedora 24 stable repository. If problems still persist, please make note of it in this bug report.