The GNU SDR types are evolving into HPSDR or high performance SDR, for use by amateur and SWLS radio systems. Developed by SDR entusiasts throughout the world, these SDRs are aimed to break the system into a number of modules, as individual modules could be developed in various locations. The modules are designed to be capable of connecting to interfaces, and they operate like plug-in boards which are used to connect a motherboard of the PC.
Such SDRs will help individuals to seek only the modules which are of interest to them, as also indulge in designing their own modules, enabling new circuits and ideas to be tested by interested operators, who may even replace the present module. Even as the majority of modules remain untouched, such experiments are possible without disrupting current working SDRs.
Such modules can range from filters with input/output interfaces, to complicated DSP activities, enabling individuals to experiment and contribute their experiences in a variety of ways to the overall system. Such modules are named to distinguish and identify them, when someone would like to discuss their components.
To summarize, the GNU SDR is an open source system, brought forward through cooperative and open endeavors. Such software is available with source code, to allow redesign, change or improve its functions. There are a number of open source licensing systems such as the GNU General Public License, commonly known as GPL, which permits the licensee to run it for any purpose that they deem fit, study its working environments, modify and even redistribute its copies.
In addition to this, the licensee can release improved design to various groups. In fact it can make you a codeveloper of SDR, helping evolution of the software. More importantly in such a situation every end-user receives, testing environment with the machine, which helps one to locate and fix a bug easily.