Welcome to the "Under the Hood" Page

This page is dedicated to giving you the inside skinny on what makes our radio panels tick and how we have gone to great lengths to give you real "instrument-like" performance in our software and a "flexible" interface that you can tailor.

This page is always being updated. Please check back for news and software and documentation updates.

Last Updated: 02/15/10

First a word about our mascot "Rowlf".
Rowlf our former QC/QA guy is rising to new heights. He has been promoted here at CallSign Software to the CEO, Chief Executive Officer, or "Top Dog!". It is his job to make sure all us here at CallSign Software deliver Top Shelf Technology to all of our users. So here are some technology notes about our products for our users.


What versions of Windows do we work with?
To date all of our software runs on Windows Win2000, XP, Vista, and Windows7, both 32-bit and 64-bit versions that support the Win32 interface. We no longer support Win95, 98 or NT4.0. You need at least a Pentium IV running at 1000 MHz to use all of features with at least 1GB of memory. Our software detects the version of Windows that you are running and applies special processing for each version as required. We also use normal graphics mode(96dpi) as we do a lot of hi-res precise pixel graphics. We use all standard 32 bit interfaces in Windows but with the countless configurations we occasionally run into an issue. When this happens we are happy to incorporate changes to accommodate yet another Windows special case.

What is DSP and DSP Filtering?
DSP, or Digital Signal Processing provides for the processing of received and transmit signals through software algorithms that filter out unwanted components of a signal. This becomes more cost effective as complex filter based electronics is no longer needed. DSP provides a set of building blocks that the Software Defined Radio Designer can use to create a set of features on a Software Radio that is consistent with its user's interests and capabilities without the need to add electronics.

How does DSP benefit me?
DSP makes possible more cost effective radios as your Personal Computer replaces the front panel. This eliminates an average cost of about $100.00 per control on the selling price of a radio. The power and falling price of the personal computer along with Microsoft Windows makes possible a whole generation of radios with more flexibility, capability, and much lower price point then traditional analog electronics based radios.

Did you know at the average cost of $120.00 per crystal filter, a DSP radio like the Pegasus and Rx-320 with its 33 filters would cost over $3300.00.

Did you know that all of CallSign Software's radio panels are based upon 32 bit arithmetic and floating point mathematics?
Even though the DSP data from the Ten Tec radios comes to us in 16-bit format we convert it to 32-bit format for greater precision. When we are manipulating frequency data, that information is all processed as floating point mathematics. This gives us greater resolution and finer precision when mapping the data to graphical displays. Why have 32 bit graphics on your fancy new Pentium class machine and only 16-bit resolution in the frequency data. It makes no sense.

How do we take advantage of DSP and 32-bit resolution?
All of our Scope Panels use DSP Signal Data right from the serial interface. We scale this data and operate on it with 32-bit precision and perform floating point calculations with it. We do not have any connections to the audio output. You are viewing actual signal data.

Did you know that the core of all of our radios is based upon a 20 MHz software clock? What is this clock?
Well it keeps everything in motion and synchronized. Our Radio panels are designed around real laboratory instruments. Of course we do not measure voltage or current, but we do measure signal strength and power output on transceivers. These measurements are gathered in real time as they are delivered. Well the software clock insures timely updates on a periodic basis or "in real time" as we say!

How can Windows and real time be spoken in the same sentence?
Well Microsoft never disqualified its Windows Operating System from being used in real-time based applications. It just that many applications do not bother with it as their data handling is not critical. The Windows Operating System has built in Programming Interfaces that can allow an application to bypass the "slower" interfaces and access the Windows core or "kernel" directly for time critical operations. We make extensive use of this interface to process signal information, perform display updates, and make timely floating point computations that affect radio panel performance. In effect we have created what is termed an "embedded real-time" system inside the Microsoft Windows Operating System.

Who or what is a Watchdog?

We shall clear up one misconception. He is not Rowlf! Anyhow every well designed piece of equipment including software has a function that keeps an eye on critical functions such as the communications between your radio and PC (Sort of like Rowlf and the staff!). One of the watchdog functions is to insure we maintain communications with the radio by periodically requesting signal information from the radio, checking the radio's response and or lack of response. We do not simply "tune your display". We tune your radio and as such insure that every frequency change command that is sent to the radio, has its response timed and its acknowledgement checked when the actual frequency display is updated.

What is our Flexible Interface?

One of the goals of the future of Software and Radio is to allow the user to define his/her radio to his/her tastes. Well a small bit of the future is now here! It was an early design goal to create a piece of software that would allow a limited number of radio components in the user interface to be changed by the user to meet his/her tastes or in affect re-define the user interface on the fly. This is possible because all of our radios are based upon a database design that tracks changes in the user interface in real-time. It is an "adaptive" database design in that it links all parts of the user interface with the radio control software in order to effect changes in the operation of the radio software in response to these user interface changes. With this basic database design we have been able to design a software based structure that is highly modular as shown in the following block diagram. The Radio Operating System Software is standard in all of our products.

How is this Flexible Interface Possible?
Well when you buy our software you are really purchasing multiple modules at once. Our software is highly modular and broken up into distinct pieces that allow us to add radio functionality, new radio platforms, and improved user interface functionality. The major parts include a Radio Communications Package, Radio Core Operating Program, Radio Database Manager, and finally User Interface Package. There are other smaller modules (such as the Watchdog) but all of these components are controlled and co-coordinated through our central database that tracks Radio Settings Changes, User Interface Changes, and last but not least the actual operation of the radio itself. We are only limited in the future by the size of your PC's memory and the speed of the machine!

What is "Point and Click" QSY?
This refers to the property that all our scope faces provide. Since our scope faces are real instrument displays, we can accurately, to 6 decimal places, track a cursor frequency wise on our scope display. Since we already provide a momentary A/B function when in split mode, we can easily provide such an interface with our scope's displayed frequency. This is great for finding those hidden signals that only the radio's DSP can see.

What is "interlinking"?
This refers to the property or ability to have two(2) radios communicate for the purpose of transferring frequency and/or mode information. The linked radios form a master/slave relationship. The master can be setup as the main radio. The slave radio can be setup as a spotting receiver or secondary console to the master. The master sends commands to the slave such as tuning commands. The slave sends status reports back to the master. This capability allows us to transfer "point and click" information from a slave to a master. Interlinking is a form of networking but in "stealth" mode. Neither the master or slave can be seen outside of the PC they are running on.

What is our tuning system and how is it different?
The tuning POD is being operated as a constant rate tuning device. This means up to a certain point, spinning the knob faster DOES NOT increase tuning speed. This must be done through the acceleration parameters you have set. The upper bound of the tuning speed is set through the tuning delay you set. This sets the frequency at which tuning changes are made independent of how many encoder ticks are gotten. The quantity of ticks per tuning delay period determines how fast the frequency's rate of change actually occurs or accelerates. A constant smooth tune actually tunes faster than a jerky fast spin. The tuning system was designed for slower systems that could get easily overloaded with the avalanche of tuning reports that can come be reported. Finally you can set the threshold at which changes in tuning rate are made. This was done to insure that tuning changes are processed at a constant rate and do not over power slower systems.

We say we use multi-processing! What does this really mean?
PegasusPlus is a full 32-bit program that contains multiple threads or processes that perform the various transceiver functions concurrently and interlinked through our database. They are designed to provide reasonable performance on the various PC types that could run any one of seven (7) different versions of Microsoft Windows(c). The thread breakdown is as follows.

-Watch Dog Monitors the state of the communications interface for line disconnect and/or communication dropout.
-Clock/Timer Performs Time processing, Station Auto Tune functions, and software clock timing.
-Meter Performs both S-meter, Tx meter, and multi-meter update and real-time draw operations.
-Main Scale Performs main scale, if displayed, update and drawing operations.
-Band Scale Performs band spread scale update and drawing operations.
-VFO A Display Performs VFO A frequency display draw operations.
-VFO B Display Performs VFO B frequency display draw operations.
-Pan Display Performs Pan Scope Display frequency and amplitude update and draw functions.
-Filter Display Performs I.F. Filter Display frequency, filter edge and amplitude update and draw functions.
-Serial Interface Performs command response dispatching and remote POD Encoder Update processing.
-Synchronizer Synchronizes the various types of main/sub/aux tuning against the appropriate tuning encoder applying both accelerated and constant rate tuning.

The serial interface thread is the highest priority thread in the system. It fields Remote POD and S-meter reports and get control above all other threads. Its priority is set at "Real Time Critical". Other than the Watch Dog, Clock/Timer, and Synchronizer thread, all other threads run at a normal rate. Blocking the Watch Dog will kill the system as it is assumed system integrity has been breached. Blocking the timer causes the system to slow down. Blocking the Synchronizer causes delays in processing remote POD encoder ticks.

What is our SWL Database format and how is it laid out on disk?

See our database page





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