As the name itself suggests, software defined radio systems (SDRs) are nothing but the radio communication systems where some software will be implemented with the help of PCs to make two way radio communication possible. There will be no more irritating circuits consisting of some typical wires and other stuff employed in software defined radio systems. As you know, in traditional radio communication circuits, you will of course find some major components such as mixers, filters, amplifiers, modulators, demodulators, detectors etc. There are also some sorts of advancement witnessed in the field of radio technology when software defined radio systems came into existence.
Here, an antenna is attached with an analog-to-digital converter in order to act as an ideal receiver. The converter is later interpreted by the digital processor of signal. It is then the stream of data is transformed by the software with the help of converter. In fact, this is the same in case of the traditional radio communication systems, where a stream of numbers is generated by the digital processor of signal. Later, the analog-to-digital converter, which is attached with an antenna, will receive the data. To be more specific, all that the SDR consists is an analog-to-digital-converter, sound card and of course a computer. The processing of radio signals are carried out by the general processors rather than using some hardware for special purpose. This design is well equipped to produce a radio, which can transmit as well as receive the radio signals with the help of different software allotted for some specific purposes.
The SDR is widely employed in the cell phone services and in military academies, as they need to be served with a wide variety of radio protocols. The SDR technology is said to be one of the most advanced technologies in the field of radio communication. This is also the only system that enables the cognitive radio. The variable frequency oscillators, filters as well as mixer are utilized by most of the receivers for tuning the signal desired into a baseband or intermediate frequency. This is where the analog-to-digital converter interprets the signal. However, tuning the signal into baseband or intermediate frequency is not required in all cases. The analog-to-digital converter samples the radio frequency signal directly in some cases i.e. after getting the signal amplified.
Unfortunately, the analog-to-digital converter used in traditional radio communicating systems will fail to identify the nanowatt radio signals; sub microvolt etc. hence, the step of conversion must be preceded by the low noise amplifiers. However, the low noise amplifiers also witness some problems in most of the cases. In fact, this is what led to the distortions in the signals that are desired. In order to avoid these problems, the band-pass filters are placed in between the amplifiers and the antenna. The flexibility of the radio is reduced by the band-pass filters. They are used to communicate with many people at the same time in many huge industries. The communication quality in software defined radio communicating systems is also outstanding. Hence, the modern world is making the most of two way radio communication opportunity offered by software defined radio systems.