Software-Defined Radio

WiNRADiO WR-G315e with a Sony VAIO laptop After the introduction of the world's first commercially available PC-based wide-band WiNRADiO receiver in 1995, WiNRADiO Communications went from strength to strength.

Today we are a major international corporation, RADIXON GROUP, supplying products to consumer markets and large government and military organizations alike.

The reasons for our success? Continuing innovation and ownership of breakthrough software and hardware technologies making it possible to integrate radio with computing to an extent never seen before, and leading the field of Software-Defined Radio that we ourselves have pioneered.

The Marriage of the Century

At the time of arrival of our first WiNRADiO receiver, the legendary WR-1000i, radio communications have been around for over 100 years and personal computers for about 30 years. Until that time, they have not been integrated closer. We had recognized the potentional for a synergy between these two key technologies, and embarked on a challenging project to produce the first viable commercially available PC Radio, a new class of communications receiver that would represent a marriage between a PC and a radio (the term Software-Defined Radio was not yet widely used at that time).

Despite many reservations and criticism from many doubters ("surely you can't put a sensitive radio in the middle of the electromagnetic storm that exists inside a personal computer!?"), we have overcome the many difficult technical challenges and the project met with a tremendous success, having started a whole new industry.

The first generation of PC-controlled radios, were such where the user-interface of a conventional receiver front panel was replaced with a far more flexible graphical user interface of a personal computer, offering additional functions and features, but with the underlying hardware remaining essentially the same.

In the second and subsequent generations, more and more hardware components were replaced by the functionality of a computer. For example, instead of using a traditional diode and a capacitor to demodulate an amplitude-modulated signal, this signal was first digitized and the demodulation process was performed by a mathematical routine executed by the computer.

This process, where more and more hardware components are replaced with software, has resulted in coining the term Software-Defined Radio (SDR) - because if the components can be replaced with software, then indeed the very functionality of these components can be redefined by this software. In contrast, the functionality of a conventional hardware component cannot be redefined; a capacitor always remains a capacitor, a diode always remains a diode.

So what are the advantages of Software-Defined Radio?

1. Design Flexibility

The recent tremendous progress of the SDR technology that we have been pioneering has been driven by improvements in available computer power, sophistication of signal processing algorithms, and, above all, the availability of fast and accurate analog-to-digital converters (ADCs) and the first processing stages for such digitized signals (typically Field Programmable Gate Arrays, or FPGAs).

This has allowed for the software to move "closer to the antenna" than ever before, which means that more and more of the conventional hardware circuitry is being replaced by software, for example filtering, demodulation and decoding functions.

No longer constrained by the inflexibility of hardwired circuitry, a SDR receiver's functionality can be changed by a software upgrade only. A completely different application class of products can be often implemented using an identical hardware platform, with the functionality defined by the software alone, thus affording a far greater flexibility to the designer than if working with hardware components alone.

2. Reliability

As hardware parts are replaced with software code (for example, a diode and a capacitor in an AM demodulator would be replaced by a mathematical routine performed on the digitized signal), and software by itself cannot break down, SDR products are generally more reliable than conventional ones.

3. Consistency and Stability of Parameters

Parameters of hardware components are subject to temperature changes, manufacturing variations and aging, often resulting in performance differences between what should be identical products. However, software always performs the same. This is why SDR products exhibit a far better parameter predictability and performance consistency between units and reduced effects of aging.

4. Upgradability

Hardware products are hard and expensive to improve and upgrade, and this typically involves changing modules, boards, etc., often requiring for the product to be sent back to the factory. In contrast, SDR products are to a significant degree "future proof" and can be improved by a simple software upgrade only, with minimum equipment downtime. New features and functions can be added easily.

Improvements in software algorithms can also lead towards improved performance or application usability of existing hardware, extending the lifetime of the product, and improving the customer's return on investment even a long time after the original purchase.

5. Reusability

Once the signal-processing or user-interface software has been developed and tested, it can be often re-used on other hardware platforms, to create new receivers or entire product families. This reduces the manufacturer's development time and cost, and in turn reduces the cost to the customer.

6. Reconfigurability

In customer-specific applications, the entire SDR product can be often reconfigured, i.e. its functionality and interface completely altered to suit changing user requirements, by a software modification alone, without the need to replace the hardware platform.

7. Enhanced Functionality

With conventional technology, certain features or facilities would be normally very expensive or even unthinkable; for example complex signal decoders or demodulators, extensive graphical-user interfaces with numerous real-time spectrum analyzers, recorders, loggers, task schedulers, test and measurement facilities, etc.

SDR technology makes it possible to implement such fuctions easily and at low cost, usually on a standard general-purpose computer platform.

For example, demodulation/decoding of certain newly introduced types of complex modulation modes is practically only feasible on SDR platforms (DRM, APCO, DMR, etc.), further underlining the "future-proof" aspect of this technology that makes it possible to defer the final design to the future, when a particular feature becomes necessary.

8. Lower Cost

Due to a reduced number of hardware parts and software reuseability, an SDR product is easier and cheaper to manufacture and maintain, hence it is typically considerably cheaper than a conventional product of comparable parameters.

Furthermore, as a greater portion of expensive RF hardware is replaced by general-purpose computer hardware whose costs continue to decline, the net effect is a rapidly declining cost of the SDR technology, while its performance keeps improving and setting new performance standards.

Internal versus External?

Many WiNRADiO receiver models are available in two form factors; external "black boxes" which are connected to a computer using interface cables, and internal PC cards than hide inside the computer. Both types have their advantages.

The advantage of the external models is in their portability, speed of installation and simplicity of interfacing. They can be operated with a desktop as well as a laptop or notebook. Rechargeable battery power supply is available as an option for many WiNRADiO external models.

The advantage of the internal models are in their neatness - there are no cables or external power supplies required, no external interface ports are occupied and no extra desk space is needed.

A computer with a WiNRADiO card inside is also very inconspicuous - nobody needs to know that there is a wide-band communications receiver hidden inside. Also, multichannel operation is simple to achieve with internal receivers, where several receivers can be hidden in, and controlled with, a single computer.

How about computer noise?

In our early pioneering days of PC Radio, this was an argument we were used to hearing all too often: Computers are strong sources of electromagnetic interference. So how is it that you can put a sensitive receiver next to, or even inside, a computer?

To start with, WiNRADiO receivers are very well shielded using special shielding methods and materials. However, we have also applied innovative, ground-breaking design methods to prevent computer-generated noise and interference from entering our receivers.

As a result, our receivers are typically less prone to electromagnetic interference than conventional receivers when placed side by side next to a computer.

Computers are ubiquitous nowadays, and our products make it possible for a radio receiver and a computer to coexist harmoniously, and enhance each another in this remarkable synergy of technologies that Software-Defined Radio represents, a remarkable technological field that we are proud to lead. One and a half decade after our first legendary radios, new legends are still being born.