Commit eea7a2eb authored by Carsten Schoenert's avatar Carsten Schoenert

Import Upstream version 22

parent 791bb514

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This file lists the analyses currently implemented into ngspice.
AC : Small-signal frequency response analysis
Table of Contents
1 Noise analysis (NOISE)
2 Operating point analysis (OP)
3 Operating point sweep Analysis (DC)
3.1 Enhancements
4 Pole-zero analysis (PZ)
5 Small-Signal distortion analysis (DISTO)
6 Small Signal frequency response analysis (AC)
7 Sensitivity analysis (SENS)
8 Transfer function analysis (TF)
9 Transient analysis (TRAN)
1 Noise analysis (NOISE)
The noise analysis does analysis device-generated noise for the given
circuit. When provided with an input source and an output port, the analysis
calculates the noise contributions of each device (and each noise generator
within the device) to the output port voltage. It also calculates the input
noise to the circuit, equivalent to the output noise referred to the
specified input source. This is done for every frequency point in a specified
range - the calculated value of the noise corresponds to the spectral density
of the circuit variable viewed as a stationary gaussian stochastic process.
2 Operating point analysis (OP)
The operating point analysis determines the dc operating point of the
circuit with inductors shorted and capacitors opened.
3 Operating point sweep Analysis (DC)
The operating point sweep analysis determines the values of output
variables while one or two specified independent voltage or current source is
stepped over a user-specified range and the dc output variables are stored
for each sequential source value.
3.1 Enhancements
Added resistance and temperature sweep.
4 Pole-zero analysis (PZ)
The pole-zero analysis computes the poles and/or zeros in the small-signal
ac transfer function. The program first computes the dc operating point and
then determines the linearized, small-signal models for all the nonlinear
devices in the circuit. This circuit is then used to find the poles and zeros
of the transfer function.
5 Small-Signal distortion analysis (DISTO)
The distortion analysis computes steady-state harmonic and intermodulation
products for small input signal magnitudes. Not all devices are supported.
6 Small Signal frequency response analysis (AC)
The ac small-signal computes the ac output variables as a function of
frequency. The program first computes the dc operating point of the circuit
and determines linearized, small-signal models for all of the nonlinear
devices in the circuit. The resultant linear circuit is then analyzed over a
user-specified range of frequencies.
7 Sensitivity analysis (SENS)
Ngspice will calculate either the DC operating-point sensitivity or the AC
small-signal sensitivity of an output variable with respect to all circuit
variables, including model parameters. Spice calculates the difference in an
output variable (either a node voltage or a branch current) by perturbing
each parameter of each device independently.
DC : DC-sweep analysis
+ Added resistance sweep as in spice 2.
* Note: It is possible to perform a generic parametric sweep ?
DISTO : Small signal distorsion analysis
8 Transfer function analysis (TF)
NOISE : Noise analysis
The (small signal) transfer function analysis computes the dc small-signal
value of a transfer function (ratio of output variable to input source),
input resistance, and output resistance is also computed as a part of the dc
OP : Operating point analysis
PZ : Pole-Zero analysis
9 Transient analysis (TRAN)
SENS : Sensitivity analysis
The transient analysis computes the transient output variables as a
function of time over a user-specified time interval. The initial conditions
are automatically determined by a dc analysis. All sources which are not time
dependent (for example, power supplies) are set to their dc value.
TF : Transfer function analysis
TRAN : Transient analysis
......@@ -4,58 +4,71 @@ Spice was originally written at The University of California at Berkeley (USA).
Since then, there have been many people working on the software, most of them
releasing patches to the original code through the Internet.
The following people have contributed in some way:
Vera Albrecht <>,
Cecil Aswell <>,
Stuart Brorson <>,
Vera Albrecht,
Cecil Aswell,
Giles C. Billingsley,
Phil Barker,
Steven Borley,
Stuart Brorson,
Mansun Chan,
Wayne A. Christopher,
Al Davis <>,
Glao S. Dezai <>,
Jon Engelbert <>,
Daniele Foci <>,
Noah Friedman <>,
Alan Gillespie <>,
Al Davis,
Glao S. Dezai,
Jon Engelbert,
Daniele Foci,
Noah Friedman,
David A. Gates,
JianHui Huang,
Alan Gillespie,
John Heidemann,
Jeffrey M. Hsu,
S. Hwang,86
Chris Inbody <>,
JianHui Huang,
S. Hwang,
Chris Inbody,
Gordon M. Jacobs,
Min-Chie Jeng,
Stefan Jones <>,
Beorn Johnson <>,
Beorn Johnson,
Stefan Jones,
Kenneth H. Keller,
Robert Larice,
Mathew Lew,
Robert Lindsell <>,
Robert Lindsell,
Weidong Liu,
Kartikeya Mayaram,
Richard D. McRoberts <>,
Manfred Metzger <>,
Paolo Nenzi <>,
Richard D. McRoberts,
Manfred Metzger,
Wolfgang Muees,
Paolo Nenzi,
Gary W. Ng,
Hong June Park,
Arno Peters <>,
Serban-Mihai Popescu <>,
Arno Peters,
Serban-Mihai Popescu,
Georg Post,
Thomas L. Quarles,
Emmanuel Rouat <>,
Jean-Marc Routure <>,
Emmanuel Rouat,
Jean-Marc Routure,
Jaijeet S. Roychowdhury,
Lionel Sainte Cluque,
Takayasu Sakurai,
AMAKAWA Shuhei <>,
Kanwar Jit Singh,
Steve Tell <>
Andrew Tuckey <>,
Charles D.H. Williams <>,
Holger Vogt <>,
Dietmar Warning <>,
Michael Widlok <>,
Antony Wilson <>,
Bill Swartz,
Hitoshi Tanaka,
Steve Tell,
Andrew Tuckey,
Andreas Unger,
Holger Vogt,
Dietmar Warning,
Michael Widlok,
Charles D.H. Williams,
Antony Wilson,
and many others...
Quite a long list, isn't it ?
Well, if someone helped in the development and has
not been inserted in this list, it is entirely my (Paolo Nenzi) fault.
If you feel you should be on this list, write to <>.
Do not be shy, I would like to make a list as complete as possible.
@end verbatim
If someone helped in the development and has not been inserted in this list
then this omission was unintentional. If you feel you should be on this list
then please write to <>. Do not be shy, we
would like to make a list as complete as possible.
This file contais a list of known but not yet fixed bugs in ngspice.
This file contains a list of known but not yet fixed bugs in ngspice.
How to submit a bug report:
* define/let commands:
the following code causes a segmentation fault:
There are two methods to report a bug you have discovered in ngspice:
ngspice 1 -> define max(x,y) ( x gt y ) * x + ( x le y ) * y
ngspice 2 -> let z = max(2,3)
vec_free: Internal Error: not in plot
Segmentation fault (core dumped)
* Bug tracker: This is the preferred method of reporting a bug.
Using the tracker on site will make your report
open by everyone and the chances of finding a fix will increase.
* ngspice-devel list: If you are a member of this list, you can write
directly to the developers' list. Do not subscribe to the list only
for sending bug reports.
The problem seems caused by the attempt to free an already freed
memory area in free_pnode and free_vec functions.
* output redirection:
ngspice 1 -> print v(1) > data.txt
This syntax does not work anymore (it worked in rework-14). If you
want to use output redirection you have to remove spaces around ">":
ngspice 1 -> print v(1)>data.txt
Before sending a bug report please note: all information you send to the bug
tracking system or on the mailing lists is public. If you need to send
sensitive information, send them to a developer directly but still write non
sensitive data on the bug tracking system to keep track of bug history.
* return value:
When ngspice is called in batch mode it returns 1 even if the simulations
are run. The problem arise when there is a .control section but no
are run. The problem arises when there is a .control section but no
.print, .plot or .fourier lines. Ngspice outputs:
Note: No ".plot", ".print", or ".fourier" lines; no simulations run
......@@ -38,3 +32,6 @@ Rework15fixed:
and exits returning 1.
Workaround: add -r <dummyfile> to the command line to avoid this.
* please refer to the sourceforge bug tracker at
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## Process this file with automake to produce
SUBDIRS = @XGRAPHDIR@ doc src man tests
DIST_SUBDIRS = xgraph doc src man tests
SUBDIRS = @XGRAPHDIR@ src man tests
DIST_SUBDIRS = @XGRAPHDIR@ src man tests
EXTRA_DIST = FAQ acconfig.h a</