Development of Software Defined Radios (SDRs)
Software Defined Radios(SDRs) is a radio communication System that uses software to modulate and demodulate radio signals. The RF signal is converted to a digital bit stream and all of the modulation and demodulation of the signal processing in a general purpose computer, or a reconfigurable piece of digital electronics. The goal of this design is to produce a radio that can receive and transmit a new form of radio protocol by updating the software code. The potential impact of software radio technologies will be profound, reaching far beyond handsets, to networks, services, applications, spectrum management and industry structures. Software Defined Radio reflects the convergence of two dynamically developing technological forces i.e digital radio and software technology. The former facilitated the wireless revolution that gave birth to the mobile phone mass market whilst the latter, over the same period, has both facilitated, and ridden, the Internet wave. NECTAR has developed a software defined radio platform for use by government and security agencies, HF frequencies are covered which help provide long distance communication using legacy and modern protocols making the platform not only efficient but also compatible with most legacy equipment in service today.

A secure packet radio modem is built in with the capability to transfer maps, photographs and other data files with zero error over long distances on HF. It is rated as one of the best by NASA for communication. Prototype Software Defined Radios (SDRs) in PPP mode were developed and delivered to various forces for testing. On successful testing the development of SDRs for operational requirement of various forces have been accomplished. They have been successfully used in CRPF, BSF and police forces of North Eastern States. Wide Band Surveillance Receivers, a modified configured.

Communication equipment intended for government, military, security, surveillance, broadcast monitoring and demanding applications has also been developed. This contains numerous advanced features such as analog and digital signals reception, three types of scanning, five types of squelch, many tuning options and virtually unlimited memories. Developed from frequency range 9khz to 8599Mhz with inbuilt computer system and wide range of demodulation Schemes. The multiple antenna system covering HF, VHF, UHF has been developed to cover wide range of communication channels. Wide Band Surveillance Receivers (WBSR) are developed in PPP mode of which 8 Nos. have been deployed with Central Reserve Police Force(CRPF) and 10 Nos. have been deployed with the Border Security Force(BSF).