Current revision is 2.64; revision history is at the bottom
of this page
Elsie™ is an uncommon commercial-grade
lumped-element ("L-C") electrical filter design
and network analysis program, directed toward the engineer
or technician involved in that line of work.
Here are some pertinent features of Elsie:
- Elsie is 32-bit Windows®
electrical filter design software nicely written to
help engineers design and analyze lumped-element
filters in the audio through microwave range. Thanks to
the standard interface, all of the various aspects of
program operation are quite easy to use. Most options
are selected by clicking on buttons. No scripts. Not a
- This filter design program designs
and then analyzes filters with a wide variety of
topologies and families and with specified orders,
bandwidths, impedances and the like. The usual filter
familes of Butterworth, Chebycheff, Cauer (including
the zig-zag transform), Bessel, Gaussian, Constant-K
and M-derived are covered.
- The quality of the screen graphics is
very high (dependent on your monitor), and include
transmission (S21), return loss (S11), transmission
with its angle, group (envelope) delay, VSWR, input
impedance and its angle and more (selected pairs of
- To maintain this level of quality,
the outputs to the printer are not "screen dumps" but
instead are from a separate set of dedicated routines
which write directly to the printer. The quality of the
graphics as delivered by the printer will be limited
only by that printer and the number of test frequency
steps used (up to 2048 steps).
- The graphics items automatically
adjust themselves to various resolution screens. As an
example, the size of the plot on monitors of 800x600,
1024x768 or 1280x1024 is the same in terms of
centimeters or inches. Aspect ratio of the screen
display can be adjusted so Smith Charts look circular
on any monitor width-to-height ratio.
- Markers can be placed on the plots.
These reveal the data for that plot at the markers'
frequencies. Up to eight markers can be defined. The
data for each frequency is shown in tabular form
beneath the plot.
- Limits areas can also be placed on
the plots. These mark the "out of bounds" area and are
useful as a tool to assist in a manual tuning
operation. Up to ten limits areas can be placed on each
plot. They are used as part of the optimization routine
to generate an error value.
- It has a Monte Carlo routine and an
extension of that forms the optimizer.
- You can tune the width and/or center
of a filter Elsie designed. Those items are adjusted
using the mouse; the filter is immediately redesigned,
reswept and replotted. Unique and fast - milliseconds
- You can select an item and adjust its
value - "tune" it - by clicking on buttons. Because the
filter design and analysis routines are very closely
coupled, the results are seen immediately on the
screen. There is no need to go to another program or
routine to see the effects of finite inductor Q, as an
- The tuning modes in conjunction with
the optimizer and limits areas allow you to easily see
the effect of adjusting a particular part, or to
achieve a response shape meeting some unusual
- It stores up to ten plots which can
be recalled for comparison. Develop a filter, store the
data plots for it, make changes to the filter, and then
recall any of those old plots. They'll be overlaid on
top of your current graph for quick visual comparison.
This facilitates a very fast visual comparison of
different families; as an example of this we can
instantly compare filters of different families
(Butterworth vs Cauer, as an example), or we can
overlay 3rd, 4th, 5th, 6th and 7th-order filters and
see the changes/differences. See the "overlay example"
- When a plot is showing, put the
cursor on the plot and press the mouse button to see a
line of data at the bottom of the screen showing all of
the information for the frequency corresponding to the
cursor position. See the corresponding data (all of the
data) at the bottom of the screen. Move the cursor and
the data line reveals the data for that new frequency.
Of course that data is also available in tabular
- It has a very flexible routine for
installing the nearest 5% values (all parts, inductors
only, capacitors only or one of those while maintaining
resonant frequencies of L-C pairs). This latter feature
is especially helpful in the design of Cauer
- It has a library of components
(including transmission lines and stubs, transformers,
arbitrarily-coupled inductors, and resistors, as well
as unique-to-Elsie parts) which can be added onto or
inserted into the schematic manually so you can see the
result. For example you can add a piece of coax
(specify the impedance and length) to the filter and
see what changes result.
- It allows manual entry of any of the
library components or changing them once the filter has
been entered. Any of those library components can be
installed or their values changed.
- It allows changing some elements to
their distributed (coax) equivalents. Easily change a
series inductor to a high-impedance line, for example.
Or a shunt capacitor to a low-impedance line.
- You can save all of the data
presented as a set of files in two-column (frequency,
data) for analysis by another program, for example an
FFT routine to see a waveform spectrum. There are
neither headers nor footers on those files to confuse
the issue. Up to nine such filesets may be saved; these
are the same files used to present the overlays.
- It does time-domain analysis as well
as analysis in the frequency domain. You can observe
the expected output from a network when it has been
excited with a square wave or a tone-burst, and even
see the envelope of a burst. See the "tone-burst"
graphics below. (The envelope of the tone-burst is
perhaps easier to comprehend visually. This is believed
to be unique with Elsie in the filter design program
- The context-sensitive Help system is
graphics-intensive (200+ graphics) and has a
walkthrough, a design example, full-text search
capability (100+ topics).
- The normalized-values for a design
are available, along with the the option to send them
to the printer; see graphic below.
- It writes schematic files for LTspice
(from Linear Technology Corp.).
[Note: Tonne Software has no connection
with Linear Technology Corp.]
- This program is designed to approach
the capabilities of the complex do-everything programs
while retaining the ease of use of lesser
- The program requires a monitor with a
resolution of 800x600 or better. Graphics are
autoscaled to accommodate higher monitor
- The program does NOT function with
computers using Japanese or Chinese-language operating
|Here are screen dumps from the program illustrating some
of the outputs to the screen. Click on them to see larger
versions; use your browser's BACK button to return.
Plot - S21 & S11
S21 with limits
S21, limits, markers
Smith 2x, markers
Envelope of burst
Monte Carlo running
Monte Carlo stopped:
Monte Carlo stopped
Overlay - orders
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This allows you to be assured of knowing about the latest
revisions to the program.
Updated to 2.64 - Corrected missing element in
Manual Entry routine
Updated to 2.63 - Total rewrite and upgrade of
Updated to 2.62 - Found and corrected errors in
Updated to 2.61 - Found and corrected error in file
reader; updated editor, file writing and file
Updated to 2.60 - Added schematic display option to
show the filter as it would be in a balanced
configuration; improved erroneous-value entry handling in
Updated to 2.59 - Clarified Cauer odd/even entry
areas; polished design and editor pages
Updated to 2.58 - Added capability to change return
loss reference value to editor page
Updated to 2.57 - Found and corrected error in
transmission line math routine when line lengths are
exactly 90 degrees; limited S11 and S21 to -120 dB
Updated to 2.56 - Found and corrected S11 and S22
phase error in Touchstone file writers (Versions 1 and
Updated to 2.55 - Added bandpass filter
Updated to 2.54 - Complete rewrite of
Updated to 2.53 - Added Entry Assistance screen;
revision of Analysis screen
Updated to 2.52 - Found and corrected error in
Cauer highpass design routine; other cosmetic
Updated to 2.51 - Complete rewrite of Wind Inductor
Updated to 2.50 - Rewrite of all subroutines for
uniform appearance; limits-editing bugfix; many cosmetic
Updated to 2.49 - Complete rewrite of circuit
editor and manual component-entry routines along with
upgrades to schematic display and design inputs
Updated to 2.48 - Complete rewrite/update of
Updated to 2.47 - Upgraded plotting screens to show
on the screen the point where the mouse-down datapoints
are being taken; Smith Chart seriously upgraded
Updated to 2.46 - Upgraded Design page to prohibit
problems resulting from missing bandpass/bandstop center
frequency, or missing topology entry
Updated to 2.45 - Corrected file-reading and
file-writing routines to ignore unused numbers in memory;
corrected Cauer normalized-value readout
Updated to 2.44 - Upgrade normalized-value routine;
added option to send normalized values to printer
Updated to 2.43 - Major upgrades to each of the
routines on the Design page
Updated to 2.42 - Major upgrade to Smith Chart
Updated to 2.41 - Major upgrade to Monte Carlo
Updated to 2.40 - Changed overlay color
Updated to 2.39 - Corrected erroneous saving of
limits areas to file
Updated to 2.38 - Corrected error causing plot type
to change unexpectedly
Updated to 2.37 - Corrected error in "specify
Updated to 2.36 - Major revision of Manual
Component Entry and Editor pages, revised menu system,
added aspect-ratio correction capability
Updated to 2.35 - Added toroidal-inductor turns
calculator, Smith Chart aspect ratio correction capability
and total re-write of menus
Updated to 2.34 - refined LTspice file-writer
Updated to 2.33 - changed order-entry to up/down
button style; forced location of Last Session file
Updated to 2.32 - discovered and corrected error in
frequency printout for regions using comma for
Updated to 2.31 - added "Instant Help" button to
the Design page to assist in Family selection
Updated to 2.30 - added "Instant Help" buttons to
the Design page to assist in Topology selection
Updated to 2.29 - updated Help system
Updated to 2.28 - added end-sections option to
Constant-k family (this in addition to the M-derived
family); updated Help system
Updated to 2.27 - editor now disallows termination
or resistor-value entries less than .01 ohms
Updated to 2.26 - correct various plot top
definition entry oddities
Updated to 2.25 - add option to show "magnified"
plot on Transmission graph to reveal detail in low-loss
Updated to 2.24 - changes to design page to prevent
design of families requiring passband ripple when no such
entry is present.
Updated to 2.23 - add M-derived family with up to
five specifiable zeros; update Help system.
Updated to 2.22 - eliminate ProLite option;
Updated to 2.21 - rewrite of bandpass
Updated to 2.20 - add nominal-value plot(s) at end
of Monte Carlo routine. Also allow overlays to be placed
on top of Monte Carlo display.
Updated to 2.19 - remove revision number checking,
fix tuning mode error.
Updated to 2.18 - added resistors to those elements
used for the Optimization and Monte Carlo routines.
Updated to 2.17 - added LTspice
Note: Tonne Software has no connection
with Linear Technology Corp.
Updated to 2.16 - total rewrite and expansion of
bandpass Impedance Matching routine and associated Help
Updated to 2.15 - added tabulated-data file
Updated to 2.14 - correct conditional errors for
Optimizer maximum-allowed-time and limit-deletion
Updated to 2.13 - correct subtle plot-color error
in Monte Carlo and Optimizer routines; upgrade Exit
Updated to 2.12 - total rewrite of Diplexer
routines and associated Help system; minor cosmetic
Updated to 2.11 - rewrite of Monte Carlo and
Optimization routines; notice design changes and suggest
saving prior to retrieving a new design; upgrade Help
Updated to 2.10 - rewrite overlay plotting
including simple deletion of overlay files; print all
overlay files on hardcopy outputs (to duplicate screen);
upgrade Help system.
Updated to 2.09 - correct error in coupled-inductor
component in the optimization routine; minor interface
Updated to 2.08 - near-total rewrite of Plot page
menu and Help graphics.
Updated to 2.07 - printing problem resolved; nearly
complete rewrite of menu and help system.
Updated to 2.06 - cosmetic only; most text size as
well as graphics now independent of screen
Updated to 2.05 - add another error-trap to Cauer
Updated to 2.04 - add error-trap to Cauer
Updated to 2.03 - all outputs to printer are now
routed via Printer Selection windows.
Updated to 2.02 - save-file (an internal operation)
now forces use of a period for decimal delineation to
allow operation in global regions which use a comma for
Released as 2.01 - June 2004