Date: Tue, 26 Oct 1993 23:52:33 -0500
Date: Tue, 26 Oct 93 13:22:45 EDT
From: Tom Coradeschi <tcora@Pica.Army.Mil>
Subject: PSPICE

Wally Patterson <patterwc@tigershark.ml.wpafb.af.mil> wrote:
>I'm looking for a MAC-based circuit simulator call PSPICE.
>Please, tell me where I can find it.

SCIENCE AND ENGINEERING EDUCATIONAL PROGRAMS FOR THE MACINTOSH

[These opinions are posted by Professor A. E. Siegman, E. L. Ginzton
Laboratory MC-4085, Stanford University, Stanford CA 94305. Email responses
directed to siegman@sierra.stanford.edu on Internet or RW.AAP@STANFORD on
Bitnet will be welcomed.]

                 ----- 
    
Messages keep appearing on Mac newsgroups asking about analog and digital
circuit analysis programs and other EE-related educational programs for the
Macintosh. This is a brief summary of Mac-based digital and analog circuit
analysis programs I know about, plus a few additional programs that may be
of interest to electrical engineering students and teachers.

The programs reviewed here are:

* B^2 Logic: a moderately priced digital circuit analysis program.

* B^2 Spice: a very good moderately priced analog circuit analysis program
based on SPICE; RECOMMENDED

* CircuitMaker 3.0: commercial but relatively low-cost program (list price
$200) combining circuit layout and drawing tool and digital circuit
simulator. Haven't tried it, but review looks good.

* Design Center PSPICE: an expensive professional-grade version of PSPICE,
operable in the Mac but only in a primitive text-file-drive form.

* DigSim: a very neat little shareware digital circuit analysis program;
RECOMMENDED.

* Electronics Workbench: described as "powerful (and modestly priced)
software to build and simulate analog and digital circuits, on screen, with
click-and-drag capabilities for adding components and connecting wires".
Haven't had a chance to try it; but ads look good.

* : an OK but not great implementation of SPICE for analog circuit
analysi

* LogiMac: another quite good small digital circuit analysis program.

* LogicWorks: said to be a student version of DesignWorks -- haven't seen
this one myself.

* Micro-CAP II: student version of a SPICE-based analog circuit program; OK
but not great.

* Micro-CAP IV: commercial version of this SPICE-based analog circuit
program.

* PARAXIA: A package of laser beam and resonator analysis programs from my
own lab, now commercially available; RECOMMENDED??? - well, others like
it.

* PSpice:  A shareware version.

* TLS: A very good wave propagation and transmission line simulator;
RECOMMENDED.

The date of writing or updating is indicated for the more recent reviews
below. Undated reviews are from 1989, 1990 or possibly earlier, and may be
out of date at this point.

-----------------------

B^2 Spice
*********

(Version 1.1, review updated May 1992)

This is an neat small-scale implementation of Spice for the Mac from a new
small company, Beige Bag Software, located in Michigan. The program allows
you to graphically wire up an analog circuit on the screen and then analyze
the circuit behavior using PSPICE. At present only the dc sweep, ac sweep
and transient analysis capabilities of SPICE are implemented and the device
library is modest, but everything is in one integrated application, and
both the circuit and the graphical outputs from the analysis steps can be
sent directly to a printer.

The program also permits you to save a circuit wired up with the graphical
editor as a SPICE input deck, so that a circuit could be wired up using the
graphical circuit editor and the SPICE deck then transferred to a more
extensive SPICE program for more detailed analysis if desired.

I've used this program some and while it still has a few bugs both it and
the following B^2 Logic program look good and are being steadily upgraded.
They are available from:

        Beige Bag Software
        715 Barclay Ct.
        Ann Arbor MI 48105

        (313) 663-4309

        71620.3474@compuserve.com

List price is $130, with student versions around $35.


B^2 Logic
*********

(May 1992)

This is a companion digital circuit design and simulation program for the
Mac from the same company as B^2 Spice. The manual and description looks
good, but I haven't tried this program, only B^2 Spice. Both of these
programs are also available in PC versions.

CircuitMaker 3.0
****************

This is a commercial but relatively low-cost ($200) digital circuit layout
and analysis program produced by MicroCode Engineering (801-226-4470) and
favorably reviewed in the August 1993 issue of MacWorld. It allows you to
lay out complex digital circuits including digital and analog components
and wiring on a very large surface (48" square), including all standard
digital circuit components, switches, LEDs, and seven-segment readouts; and
then simulate the circuit operation, including observing the signals at
various points using scrolling chart displays, and watching the dynamic
operation of the LEDs and seven-segment displays.

Haven't had a chance to try this, but sounds good.


Design Center PSPICE
********************

(May 1992)

This is an extensive new professional-level implementation of PSPICE for
multiple platforms including IBM-PC with DOS, IBM-PC with Windows 3.0, DEC
VAX, SUN and Macintosh announced in 1992 by

        MicroSim Corporation 
        20 Fairbanks 
        Irvine CA 92718

        1-800-245-3022,
        (714) 770-3022 
        (717) 455-0554 (fax)

MicroSim also distributes (or used to distribute) the IsSPICE program
described below.

This package provides a very complete and extensive professional version of
PSPICE with extensive libraries including European devices, together with
schematic capture, PSPICE modeling of mixed-mode analog and digital
circuits, statistical analysis, stimulus generation, graphical waveform
analysis, and device characterization all in one package. However, the
Macintosh version of the package still operates only in a very primitive
text-file-driven mode on the Macintosh. In particular, while the Design
Center package apparently provides for graphical circuit editing and a
primarily graphical user interface in the PC Windows version, but _not_ on
the Macintosh.

The Macintosh version is priced at $550; versions for other platforms run
to multiple thousands of dollars. A free evaluation version with some
limitations was available to educators as of April 1992.


DigSim 2.0
**********

(Review updated May 1992)

DigSim is a shareware program written by Brian Rauchfuss, 8915 N 13th
Avenue, Phoenix AZ 85021 (this is an old address and is probably no longer
valid; information on an updated address would be appreciated). This
program is currently available as version 2.2 in the "app" section of the
info-mac archives at sumex-aim.

This is one of my favorite programs: small, neat, user-friendly, very
Mac-like, and cleverly done. When you open the program there is a palette
of standard digital components including toggle switches, LEDs, inverters,
and multiple kinds of logic gates and flipflops displayed at the side of
the screen. Using the mouse pointer (which neatly turns into a soldering
iron) you can click and drag these elements out onto the screen and wire
them up into a digital logic circuit of any complexity you wish.

Multiple wires can be connected to the "solder points" on each element, and
neat "square-corner" layout of the wires between any two circuit elements
is taken care of automatically by the program. A menu selection allows you
to turn the mouse pointer from a soldering iron into a pair of wire
clippers, which you can use to cut away any wires or elements you want to
remove.

As soon as the circuit is wired up you can use the mouse to switch any of
the toggle switches in the circuit ON or OFF; and by connecting LEDs to any
points of interest in the circuit you can watch the resulting logic values
at these points switch HIGH or LOW. As an example, if you want to
demonstrate one of DeMorgan's theorems, you just wire up a pair of switches
so that they drive the inputs to both forms of the logic statements
appearing on opposite sides of the theorem, and see visually that for every
possible combination of inputs, the LED responses at the outputs of the two
circuits are the same.

In addition, you can open a simulation window which will display the input
and output waveforms versus time at multiple selected points in the
circuit, just as they would be seen on a multi-beam oscilloscope. You can
draw arbitrary binary waveforms for each input point using the mouse, and
then see what the outputs will be at other points, with a choice of times
scales for the horizontal axis. There is even a small fixed logic delay or
switching time associated with each element, so that the effects of gate
delay can be envisioned.

Much more complex circuits can of course be wired up and tested, as well as
saved for future use; and in addition multielement circuits can be saved as
"black boxes" with multiple inputs and outputs for use as building blocks
in still more complex circuits.

All in all, this is everything a small educational or demo program should
be. Despite being written in 1986 (or earlier) it seems to run fine under
Multifinder. I recommend it highly as an "on-screen digital logic lab" for
class demonstrations, student experimentation, and the like.


Electronics Workbench
*********************

(Revised March 1993)

I've only seen advertisements for this program, not tried the most recent
version myself; but to judge from the brochures this is a relatively
inexpensive program (around $200 for the ``personal'' version) for wiring
up and analyzing analog and digital circuits on the Macintosh screen. The
program is described in a 1992 advertisement as "the electronics lab in a
computer" with "powerful software to build and simulate analog and digital
circuits on screen", including click-and-drag capabilities for adding
components and connecting wires. There are separate analog and digital
modules

In common with DigSim and in contrast to B^2 Spice, this program displays
all the available circuit components as icons in a scrolling "parts bin" at
the side of the screen; you select components from these, using the mouse
to drag components on the screen. There are also a number of test
instruments including a pulse and function generator, a ``Bode Plotter''
(swept frequency analyzer), and an oscilloscope in the analog module, and a
word generator, logic analyzer, and logic converter in the digital module,
which you drag on to the screen and wire into your circuit. The screen
graphics in the brochure look quite good.

According to the advertising Electronic Workbench uses SPICE as its
analytical engine. Both PC-compatible and Mac versions are available; I
would say that an earlier Mac version that I tried clearly showed its PC
origins, with the interface not being very Mac-like. Electronic Workbench
is available from

        Image Technologies 908 Niagara Falls Blvd North Tonawonda  NY
        14120-2060

        (416) 361-0333
        (416) 368-5799 (fax)

IsSPICE/PSPICE (Mac Classroom Version)
**************************************

IsSPICE/Mac is a commercial version of SPICE for the Macintosh available
>From MicroSim Corporation (see Design Center review for address) which was
available for $95 (no coprocessor version) or $295 (coprocessor version.)

MicroSim distributes a series of both student and professional versions of
PSPICE for use on a variety of Apollo, DEC, IBM DOS, Macintosh, OS/2, and
Sun machines. This student version of PSPICE for the Mac appears to be a
pretty complete professional-grade version of the well-known SPICE program,
except it's limited to about 10 transistors and 25 nodes and has a reduced
version of the SPICE library.

Unfortunately, what the program provides is just plain old 1970s-style
SPICE with the same antiquated text file data input and output methods; no
ability to wire up or view circuits as on-screen schematics; and little or
no adaptation of the program interface to the Mac. You also still have to
first run SPICE on the input data file to carry out the analysis and then
run another program, Probe, as a separate program to view the output
waveforms; and the viewing capabilities and command interface in Probe are
pretty primitive by modern standards.

SPICE itself is of course a powerful, highly developed, and widely used
piece of circuit analysis software. If you like SPICE itself, or if you
just enjoy running programs with IBM PC interfaces on the Mac, this will be
fine with you. But if you're looking for a _Macintosh_ circuit analysis
program, forget it.

[Could someone make up a HyperCard interface that would let you draw your
circuit and automatically prepare the associated input text file in
HyperCard, then launch SPICE and Probe from HyperCard buttons?  Might be
one way to put a Mac interface on this program.]


LogiMac 1.21 
************

LogiMac is a small digital circuit analysis program written by Chris
Dewhurst of Capilano Computing in Canada. It was formerly distributed by
Kinko's Academic Courseware Exchange, which is unfortunately defunct. It is
now available from the Intellimation Library for the Macintosh (see the TLS
description below for the address).

This is also a good program for digital and logic circuit analysis, perhaps
even a little more capable than DigSim. It comes with good documentation
and I give it a very favorable recommendation, though I like DigSim a
little better and therefore have used it much more. This is primarily
because the individual elements in DigSim are visible on screen in a
palette, while in LogiMac the elements are all listed in a long menu, and
you have to pull the menu repeatly to access a new element to add to the
circuit. Other than that the capabilities of the two programs are quite
similar.

One other problem is that the version 1.21 of LogiMac which I have is dated
1985 and will not run under Multifinder, at least not on my Mac II or SE/30
running System 6.0.5. On the SE/30 it gives the error message "Invalid
Illegal Instruction: ---- 3000". [Does that imply there can somehow be
"Valid Illegal Instructions" ?!?]  If a new version is or will be available
>From Intellimation, perhaps this problem will be solved.


LogicWorks
**********

(February 1993)

around $300 from

        Capilano Computing
        1168 Hamilton St.,  Ste. 501
        Vancouver BC V6B 2S2
        Canada

Substantial educational discounts are also said to be available.



Micro-CAP II (Student Version)
******************************

(Review from 1990 or thereabouts.)

This is an older student version of the analog-circuit analysis program
Micro-CAP IV which was originally developed (I believe) for the IBM PC
world. It's available commercially from Spectrum Software (see review of
Micro-CAP IV below for address). The price is right (around $40); the
general approach is right (you can wire up circuits on screen by selecting
elements from a palette and pointing and clicking on screen); and if the
details were just a little better executed, the whole program would be
just right. Unfortunately it isn't.

As mentioned, the program opens up with a Circuit Window; a Components
Window, i.e., a palette of standard components like RLC elements, diodes,
transistors, batteries, pulsed and sinusoidal time-varying voltage and
current sources, op amps, and so on; and a Library Window in which one can
select or define values for named components. Using a slightly awkward
approach one can click on an element in the palette to select it, click in
the circuit window to create a copy of the element there, and then type in
a numerical value or a logical name for the element.

Unfortunately the troubles start right there. If you want to create a 100
picofarad capacitor, after clicking to position the capacitor you have to
type "100PF" EXACTLY -- not "100 PF" or "100pF" or "100 pf". The program
will accept all of these other inputs, with no indication of any trouble --
but "100 PF" for example will give you 100 FARADS instead of 100
picofarads. Similar complications arise in trying to assign values to
resistances or inductances in ohms, kilohms, microhenries, and so on: "1K"
gives 1 kilohm, but "1 K" doesn't; I guess it gives 1 ohm. In general
neither adequate input error checking nor the "pico, milli, Mega" concepts
of SI have made it into this program yet.

To keep things interesting if hardly consistent, if you want to put in a
10-volt battery, you have to click and then type just plain "10", not "10V"
or "10 V" -- neither of which will be accepted at all.

Once a circuit is wired up on screen, you can insert, delete, or change the
value of elements, using the mouse; and then carry out transient, DC or AC
analyzes.

The transient analysis does a time-domain solution with single or repeated
pulsed signal inputs of various kinds. There are 16 adjustable parameters
(time scales, time steps, error criteria, output voltage points, etc.) for
the simulation; these can be edited (in a rather awkward fashion) in an
"edit window" which operates essentially like a Mac dialog box. You can
then run and display the transient analysis on screen, displaying 4
separate voltage waveforms versus time. The analysis parameters and the
output waveforms can also be printed or dumped to disk files.

The DC analysis finds the DC response of the circuit (which may be linear
or nonlinear) and displays a plot of the output voltage at one selected
node versus the input voltage at another selected node, with everything
else in the circuit held constant. Again there are multiple parameters,
such as choice of input and output nodes, input voltage range and step
size, and so on, that can be edited; and the results can be printed or
saved.

A third mode is an AC analysis or Bode plot which plots gain in dB, phase
shift in degrees, and group delay in time units versus frequency for
selected input to output points of a circuit. The frequency axis is on a
log scale with selectable lower and upper frequency values and frequency
steps.

The program also has user-defined waveform generation capabilities and a
Fourier Analyzer module, which I have not explored.

This program has the promise of being very valuable and useful, but
unfortunately the difficulties I mentioned above, plus others I'll mention
below, put me off sufficiently that I stopped trying to make any
substantial use of the program even though I teach an undergrad
intermediate electronics course in which it could be most useful.

My first effort, for example, was to use the MOS transistor model in the
program to wire up an elementary two-transistor enhancement-load MOSFET
logic gate such as we were analyzing in class. Neither the transient
analysis nor the dc input-output characteristics of this gate were
correctly simulated by the program. In an attempt to understand this, I set
up a simpler circuit just to display one curve (for one fixed gate voltage)
of the IDS versus VDS characteristic curves of a single MOS transistor.
That didn't come out right either. A call to the vendor revealed that this
can't be avoided, due to some problem in the MOS dc response related to the
way the body of the MOSFET is handled (though if the manual is to believed
this shouldn't even matter at all). (This may be corrected in newer
versions.)

Playing with other circuits gave somewhat better results; though in general
the numerical simulations using default parameter values seemed very crude
and inaccurate. Simulating the decay of a simple RLC circuit, for example,
gave transient results hardly recognizable as a sine wave, and with a very
inaccurate value of damping rate.

I imagine the program can probably be made to perform better with better
tuning of the parameters employed in the simulations, though probably at
the cost of considerable slowing down of the calculations. I'd want to see
a much more "bullet proof" and reliable program, however, before turning
something like this loose on inexperienced students.

Other complaints are that the overall implementation of the Macintosh
interface is awkward and poorly done, and there are many "buggy" aspects to
the program. The windows lack zoom or go-away boxes, and the command keys
violate Mac interface standards. A menu command is supposed to display the
node numbers in the on-screen circuit schematic; it doesn't work on my
machines. You can print the circuit netlist using a menu command, but not
display it on screen or edit it. The manual tries to be helpful, but is
basically inadequate.

The program may or may not be compatible with Multi-Finder; it seems to
encounter different difficulties when I try to run it under MF on my two
different machines. Sometimes it can't find the required Library file; when
that happens it freezes rather than opening a SFGetFile dialog box.

All in all, I hope a much better version of this program (at the same
reasonable price) will eventually appear. According to the vendor a
"Micro-CAP IV" version for the Macintosh is in the works, but won't be out
for some time -- another year at least. Until then, you might find this
program useful; but I don't recommend it.

Micro-CAP IV
************

(May 1992)

This is the upgraded professional version of the Micro-CAP program which is
being advertised in mid-1992 as available for both Macintosh and PC
computers. It is said to include direct editing and SPICE analysis of
on-screen circuit schematics, and direct display of graphic results. It's
available from:

        Spectrum Software
        1021 S. Wolfe Road
        Sunnyvale  CA  94086

        (408) 738-4387
        (408) 738-4702 (fax)

The list price is $2495; whether an updated student version is available is
not indicated.


PSpice (shareware version)
******

(February 1993)

A shareware version of PSpice is said to be available via ftp from
info-mac@sumex-aim.stanford.edu. I have not tried it.

PARAXIA(TM)
***********

This is a package of four programs intended for simulating and analyzing
laser cavities, optical lensguides and optical beam propagation (Fresnel
and Fraunhofer diffraction) written by graduate students in my research
group at Stanford University.

The "ABCD" program carries out complex-valued ray-matrix and
Hermite-gaussian mode analyzes for arbitrary complex-valued paraxial
resonators and lensguides with two separate transverse dimensions,
including astigmatism and misalignment in each individual element.

The "FRESNEL" program uses FFT and FHT methods to propagate an arbitrary
optical wavefront through any arbitrary paraxial optical system using
Huygens diffraction integral in one rectangular or one radial transverse
coordinate, in either the Fresnel or Fraunhofer domains. A combination of
scripting capabilities and masking facilities allows for such things as
iterative Fox and Li optical resonator calculations as well.

The "VSOURCE" program implements the so-called virtual-source method for
calculating the lowest and higher-order eigenvalues and eigenmodes in
so-called unstable optical resonators with both circular or strip mirrors
over a wide range of Fresnel numbers.

Finally a "VRM" program carries out some simple mode calculations and
design analyzes for gaussian variable-reflectivity-mirror (VRM) optical
resonators.

The outputs from the different programs can be displayed on screen,
printed, exchanged between programs or saved to disk in various formats,
especially including formats which will feed directly into major Macintosh
graphics programs.

These programs are intended primarily for those studying laser beams and
resonators and laser beam propagation; I'll leave it to others to assess
their quality and value. Note that this package does not provide any form
of the conventional ray-tracing programs, showing rays propagating through
simple lenses and the like. A number of such programs are commercially
available, however, and would obviously be of interest for teaching
elementary optics.

This program was formerly distributed by the Stanford University Software
Distribution Center, but is now being commercially distributed by

        Genesee Optics Software, Inc.
        3136 Winton Road South
        Rochester NY  14623

        716-272-9944
        716-272-8108 (fax)

and is only available from them. An education price for academic
institutions is supposed to be available.


TLS: Transmission Line Simulator
********************************

(May 1992)

TLS or "Transmission Line Simulator" was written by Charles Roth, Jr., of
the University of Texas at Austin. I have used it in teaching an undergrad
EM theory course, and recommend it enthusiastically.

What you see on the screen with this program is a section of transmission
line which you can terminate with an arbitrary impedance load at the output
end and an arbitrary source impedance at the input end. You can then launch
a wide variety of waveforms -- single pulse, multiple pulses, sinusoidal
tone bursts, CW sinusoidal signals turned on at t=0 -- from the source end;
and watch the voltage and/or current waveforms on the line move down the
line, reflect off the output end, and continue bouncing back and forth on
the line. You can view either a kind of dynamic instantaneous display of
V(z,t) or I(z,t) versus time on the line, or a form of integrated display
in which a shadowy echo of earlier curves makes the standing-wave patterns
on a line very visible and graphic.

Extensive capabilities exist to pause the simulation so you can examine and
discuss the instantaneous waveform before continuing; or you can turn off
the input wave and let a pulse or tone burst rattle back and forth,
decaying with time; or you can tune the input CW sinusoidal signal so that
you see the resonant response in a line with large end reflectivities, or
in a laser cavity equivalent. The loss in the line itself, the end
impedance, and other parameters can be set or changed during operation in a
flexible fashion.

The program interface is a little complicated to learn at first, but one
rapidly becomes comfortable with it. The numerics of the simulation seem to
be very well thought out, so that the program always seems to give accurate
and reliable results, and to operate with acceptable speed.

All in all, I find this an excellent, very useful and very well implemented
program, and I recommend it to anyone teaching or studying transmission
theory, waveguides, or EM theory. It is available from

        Intellimation Library for the Macintosh
        P. O. Box 1922
        Santa Barbara CA 93116-1922

        (1-800-346-8355)

The Intellimation catalog also contains a number of other useful
educational programs for the Macintosh, in both technical and nontechnical
fields.
 
Hope this helps...

                tom coradeschi    <+>    tcora@pica.army.mil