Colin's Software Page

Circuit Scribe

Circuit Scribe is a circuit/schematic drawing and netlisting program that I have created to give me the ability to illustrate my Electronics web pages.

To install, simply extract the Setup.exe file from the downloaded CCTScr.zip file, and run it. There is an uninstallation tool on the Start menu. Example project and library files are included.

Circuit Scribe is free for personal users. It should run on Windows 98, 2000, and XP.

Download
CCTScr.zip [1188KB]

Version 1.0.0.0

Updated April 7, 2005

On-line help files for the software: Circuit Scribe Help

With Circuit Scribe software, you can:

Create and print circuit diagrams (schematics)
Create screen-capture graphics for use in illustrating web pages
Export netlists to PCB layout software
Export netlists to Spice circuit simulation software
Export Bill of Materials lists
Automatically create new component outlines by importing IBIS files

Layin's line and colour editing features allow you to create illustration quality layouts as well as doing routine circuit design and documentation.

To illustrate this, I created an example of a circuit illustration (part of which is shown below), based on an illustration that I created originally in 2001 (in the page thumbnail on the right) for publication (Seymour C J, "The Road to High Frequency Applications for SiC Power Diodes", Power Electronics Europe, Issue 6, 2001).

The example started with standard general library components from the library file "LayIn.lib", which were then modified to thicken lines and include different fill colours in certain component objects, creating the library "Illex.lib", which is also provided in the library samples when Layin is installed, and the circuit layout was further augmented with text and drawing elements, resulting in the example file "PwrOsc.cct".

Thumbnail image of page from Power Electronics Europe, Issue 6, 2001

Extract of Power Oscillator Illustration

For the entire illustration layout, click here.

RFPROP

Version 1.10

Updated January 4 2004

This is a 32 bit version of RFProp, distributed with an improved installation program based on the Nullsoft installation system.

Functionally it is the same as the previous version, except that non-standard .ASC file extensions have been replaced by .TXT, a default file extension is now added if it is not specified in the save file dialog, and the units quoted for "Margin at spec. range" have been corrected from m to dB. The 32 bit file-save common dialog is a considerable improvement on the old 16 bit one.

Download
Note: Install rebuilt with newer version of NSIS because of virus alert, believed false, by GriSoft AVG after June 29 2005 267.8.7/34 signature updates. rfp110a.zip [96KB]

Version 1.03

Updated June 24 1998

This is a Windows propagation calculator for the transmission path between an RF transmitter and a receiver. It is aimed mainly at free-space and space-wave applications, such as are encountered in VHF, UHF and microwave communications, and also in satellite communications. A knife-edge diffraction calculation is also included which when enabled allows the effects of a hill or other obstruction to be taken into account.

Please click on the above image to view it in more detail.

Download rfp103.zip
rfp103.zip [83KB]

SimTel distribution:

  rfp103.zip   win3      ham  Free Radio Propagation & Diffraction calc 1.03

http://www.simtel.net/pub/pd/3067.shtml
http://www.simtel.net/pub/dl/3067.shtml
or enter rfp103.zip in the search box.

Some minor changes were made to the install.txt file on 22/6/98

Additional Information / FAQs for RFProp version 1.03/1.02

None

Additional Information / FAQs for RFProp version 1.01

Receiver Sensitivity

Receiver sensitivity (receiver power) is a calculated result rather than an input term. Sometimes it is desirable to use receiver sensitivity as an input parameter for a calculation.

In RFProp, receiver power (Min.) is the minimum power required at the receiver input. This is the signal level that must be available from the transmitted signal to achieve the signal to noise ratio required by the signal demodulator. It is defined by the receiver temperature, noise figure, bandwidth, and signal/noise ratio required for whatever modulation scheme is in use.

The minimum required receiver power is kTBSN where:

k is Boltzmann's constant
T is the temperature in degrees Kelvin B is the bandwidth in Hz
S is the signal power / noise power ratio
N is the noise figure (as a linear multiple, not dB as entered in the software)

These parameters are specified as they are more fundamental than receiver sensitivity.

If you wish to use a receiver sensitivity figure, start off with the default values, look at the calculated receiver sensitivity, and modify one of the fundamental parameters T, B, S or N as described above so that the calculated receiver power is the same value as your specified receiver power. If you know three of the parameters you should alter the remaining one to arrive at the receiver sensitivity. If you don't know the fundamental parameters, it doesn't really matter which one you alter as long at the resulting receiver power is the value you need to specify.

For example, assume initially you have Rx Noise Figure 6dB, Signal Bandwidth 10000 Hz, Rx Detector S/N 16dB, and Temperature 290K, then the receiver power (Min.) will be calculated as -111.977 dBm.

If you have a receiver sensitivity specification of -118 dBm, you can change the Rx Detector S/N to 9.977 dB (i.e. 16 - (-111.977 - -118) ) then the receiver power (Min.) will be calculated as -118 dBm.

Once you have set the minimum receiver power figure for the setup you are using, it should remain the same regardless of the path loss being calculated. The difference between the minimum required receiver signal power, and the actually received signal power, gives you your signal margin.

Window Size

Q: When I attempt to maximise RFProp or increase the size, it does not work.

A: The window can not be enlarged because it is designed to fit the fixed-size image background. It can only be shown in minimised (icon) or normal form.

Text / Parameter Boxes do not fit

Q: The control boxes and text appear to be truncated.

A: This appears to be a problem with font sizes on Windows 3.1. The program is supposed to use the default "System" font with all standard default settings for the illustration text. This is corrected in version 1.02+. Otherwise, try upgrading fonts, changing to a higher resolution display, or upgrading to a higher version of Windows.

Field strengths are not calculated correctly

The text output window reports power density as 0.1 times the correct value (-10dB). This is corrected in version 1.02+.

If Propagation Law is not 2, range & margin do not agree

It has been reported that the range and margin at nominal range do not tie up if any propagation law other than 2 is used.

Parameters which reproduce the problem:
If a propagation law of 4 is used and the power is adjusted so that the MAX range = the nominal range at 100m, then the resulting margin at nominal range is given as 28,706 dB instead of the correct answer of 0dB, as it does in the case where the propagation law of 2 is used. This is corrected in version 1.02+.

Version Information

RFProp version 1.00, 11/10/96, was never publicly released.

RFProp version 1.01, 18/10/96, was initially distributed at the 1996 Radio Solutions Conference at the National Exhibition Centre, Birmingham, England, at which the author delivered a paper on spread spectrum radio. RFProp was part of a free promotional disk handed out at the Central Research Laboratories stand in the industry exhibition associated with the Conference.

RFProp version 1.02, 12/6/98, has been revised to fix bugs, and make improvements that were mostly suggested by interested users.

RFProp version 1.03, 19/6/98, had missing units of dBm added to the Input Intercept annotation.

Principal Changes in version 1.03:

You can now maximise RFProp or increase the window size. Previously it was fixed at the size of the bitmap that forms the background image.

Some users reported that control boxes and text appeared to be truncated; to alleviate this the ability to change fonts and resize the window has been added. The selected fonts are saved in the RFProp.ini file for the next session, but the window size will revert to normal.

In version 1.01, if a propagation law of 4 is used and the power is adjusted so that the maximum range equals the nominal range at 100m, then the resulting margin at nominal range is given as 28,706 dB instead of the correct answer of 0dB, as it does in the case where the propagation law of 2 is used. This was due to an error in calculation which has been corrected in version 1.02+.

Intermodulation calculations have been added, with an extra input intercept input parameter.

Text output window reported power density as 0.1 times the correct value (-10dB); this has been corrected.

A "Tip Help" window has been added, so that previous results stay visible during input editing.

References

Some references are given in the help file, and are repeated below.

Some additional references that may be of general interest (included in version 1.02+ help):

Antennas, F. R. Connor, 1972, Edward Arnold ISBN 0 7131 3279 5
Radio Wave Propagation and Antennas, An Introduction, John Griffiths, 1987, Prentice-Hall ISBN 0-13-752304-1
Mobile Communications Engineering, William C. Y. Lee, 1982, McGraw-Hill, Inc., ISBN 0-07-037039-7
Concepts and Results for 3D Digital Terrain-Based Wave Propagation Models: An Overview, Thomas Kurner, Dieter J. Cichon, Werner Wiesbeck, IEEE Journal on Selected Areas in Communications, Vol. 11, No. 7, September 1993
Terrain-Based Propagation Model for Rural Area- An Integral Equation Approach, Jan T. Hviid, Jorgen Bach Anderson, Jorn Toftgard, Jorgen Bojer, IEEE Transactions on Antennas and Propagation, Vol 43, No. 1, January 1995
A Power-Spectral Theory of Propagation in the Mobile-Radio Environment, Michael J. Gans, IEEE Transactions on Vehicular Technology, Vol. VT-21, No. 1, February 1972
Modelling and Simulation of Mobile Satellite Propagation, R. Michael Barts and Warren L. Stutzman, IEEE Transactions on Antennas and Propagation, Vol. 40, No. 4, April 1992

From Help File:

E. N. Skomal, A. A. Smith, Jr., Measuring the Radio Frequency Environment, Van Nostrand Reinhold 1985.
R. Davies, A. Simpson, J. P. McGeehan, Preliminary Wireless Propagation results at 1.7 GHz using a half wave dipole and a leaky feeder as the transmitting antenna, 1993.
800-MHz Attenuation measured in and around suburban houses, D. C. Cox, R. R. Murray, and A. W. Norris, AT&T Bell Labs Tech. J., V. 63, No. 6, July-Aug 1984.
E. H. Walker, Penetration of Radio Signals into Buildings in the Cellular Radio Environment, Bell System Tech. J., V. 62, No. 9, Nov. 1983.
P. W. Huish & G. Pugliese, A 60 GHz Radio System for Propagation Studies in Buildings, 3rd int. conf., on antennas & propagation.
S.T.S. Chia, D.R.Greenwood, D. C. Rickard, C. R. Shepherd, R. Steele, Propagation studies for a point-to-point 60GHz microcellular system for urban environments.

Web links of interest:

WinShoe IRC Client [V. 1.34 released July 15, 2001]

Download
Winshoe.zip [390,620 bytes]

SimTel distribution:
Enter wshoe134.zip in the search box.

WinShoe is an Internet Relay Chat (IRC) client for connecting to IRC networks and finger servers on Windows PCs. Features multiple IRC network connections, aliases and popups, scripts, text searches, wheel mouse, Ident and finger servers, browsing URLs, three colour modes compatible with most existing software, 16 and 32 bit versions.
WinShoe

Main windows and controls
WinShoe

Server, channel and private windows

Popup menus

Y2K: Check your Real Time Clock / DOS Clock Compliance

Includes source code

Please click on the above image to view it in more detail.

There are two fundamental clock systems in PCs using DOS and Windows. Your DOS clock may roll over to 2000 OK, but the real time clock (RTC) in the embedded clock chip may (for example) roll over to 1900- you won't see this until the PC next re-boots and loads the DOS clock from the RTC. Perhaps you have run a Y2K check on your machine or your IT department has put a "Y2K Compliant" sticker on it, but you would still like to see for yourself on Jan. 1st?

Below, you will find a FREE clock checking utility written by me that will help you to check BOTH clocks. You can use it to see if your remediation software really has worked- does your software allow you to actually SEE the two clock settings?

Have your PCs been tested for the Crouch-Echlin effect? Have you even heard of it? Has your IT department advised you about it? This effect too is associated with the two fundamental PC clocks.

There will certainly be PCs that fail due to insufficient preparation or lack of awareness of the fundamental two-clock problem. The simultaneous occurrence of PC failures, even a few small percent, could have a significant effect on the global economy as hardware fails, time is spent carrying out fixes, and valuable data is lost!

My program is a read-only program that does not alter your setup in any way (however, no warranty or guarantees can be made- it is a free utility!).

About the Y2K date problem: Two Clocks

The PC contains two clocks - one is a built-in hardware clock usually in an embedded chip (real-time clock, or RTC). This one keeps the time when the system is powered off.

The system clock (or DOS clock, or virtual clock) is set once from the RTC when the computer is turned on. The correct functioning of this process is one of the most fundamental requirements for Y2K compliance.

While it is still possible to read the RTC and use that, after boot-up, as this program does, normally applications work exclusively from the system clock.

The operating system (e.g. DOS) maintains the system clock via a count updated at 18.2 times per second. This count is converted to hours, minutes and seconds whenever the time is read.

If the RTC fails to work properly in Year 2000, any error may go un-noticed until your next re-boot or power-down/power-up sequence.

For further information on SEERTC including limitations and cautions, see the README.TXT file within the zipfile.

The Crouch-Echlin effect manifests as a time-shift relative to real time every time you boot-up. If you check the RTC and DOS clocks after re-boot for a valid current time, you should be able to identify any time-shift due to this (or other causes). Note that a small time-shift could easily go unnoticed, resulting in problems eventually occurring after a number of re-boots. Examining and comparing the two clocks directly is therefore very useful.

You can also check the Y2K leap year calculation!

Download seertc11.zip (Includes source code)
SimTel distribution:
Enter seertc11.zip in the search box.

Reference web sites

These sites are provided for information, but it is not possible to guarantee their reliability, safety or security. You should take appropriate precautions against unsafe advice, software, viruses, etc. and you are advised to seek the advice of a suitably qualified IT professional.

RFGLOSS

This is a Windows help file organised as a glossary of terms encountered in low power radio. The background to this collection of terms is that in the UK, since the late 1980s, the government radio regulatory authority has deregulated parts of the radio frequency spectrum where radio systems are used with low power and over relatively short ranges, for applications such as security systems, remote control and telemetry for industrial applications, "panic-buttons" for emergency and nurse call type systems, electronic doorbells, radio car door openers, etc. The subject area is also influenced by the author's background as an industrial representative to the Low Power Radio Association, an organisation linking industry and government radio regulators in the UK and aiming to facilitate communications and representations between the regulators and the companies involved in the technology. The author has also delivered papers at two of the Low Power Radio Association conferences, including the 1996 Radio Solutions Conference at the National Exhibition Centre, Birmingham. The glossary, and the other two programs above, was first distributed as a free promotion at the industry exhibition associated with this Conference.

Download RFGloss
Available on SimTel:
Enter rfgloss.zip in the search box.
97772 bytes

HIERSAVE

This is a Windows Screen Saver (Freeware) which includes scrolling Hieroglyphics, a typewriter effect with user-configurable bitmaps, and floating bitmaps (again, user-configurable). A "tennis" mode adds an classic video game element (PONG) to the floating bitmap. The floating bitmaps are also user-configurable.

Download Hiersave
Available on SimTel:
Enter hiersave.zip in the search box.
339052 bytes

Related topic: Screen Saver Heaven site

Any comments on the above downloads should be e-mailed to the email address shown at the foot of the page.

Under Development

AnaCirc Circuit Simulator and Optimiser

This is something I have developed for my own use. I don't know if I will make it publicly available because there is a considerable amount yet to do to make it 'complete'.

RF amp using HFET1101 - now using microstrip line simulation (based on T. Ha, Solid-State Microwave Amplifier Design, John Wiley & Sons, 1981)

RF amp using HFET1101 - Ideal transmission line version

Single-ended amplifier using NEC70000, 6 to 18 GHz [Compare with Touchstone sample AMP6_18.CKT]

RF Amplifier using Mini-Circuits MAR-4 MMIC

This illustrates an AnaCirc simulation of a simple RF amplifier stage, using a Mini-Circuits MAR-4 amplifier, incorporating the IC's S-Parameter data combined with coupling and bias components.

RC Integrator Network - Small Signal Time Domain Response [R=1k, C=50n]
Please click on the above images to view in more detail, or click on a link to view the image.

AnaCirc is a circuit simulation program which features:

Frequency domain small-signal network analysis
Time domain Fourier response analysis
Lumped components (e.g. Resistors, capacitors, inductors, transistors)
Distributed components (e.g. transmission lines)
Subnetworks that can be included in heirarchical networks
Linear and Log frequency sweep, and spot frequency analysis
Graph plotting to cartesian and polar (Smith) coordinates
Variable Substitution
Target specification and circuit optimisation
Reads industry standard S-Parameter files
Output of voltage gain, S, Y, Z parameters, real/imag, mag/phase or decibel magnitude
Output listing from any sub-networks

Other freeware/shareware software sources

March 9th, 1997 Updated Oct 26th, 2005