## What is software defined radio

Very simple to answer. The SDR (that’s the acronym) is a new concept that is arising since 30 years in the ham radio (but not only) field.

It was the 1983 when the first software defined radio was introduced. That’s because semiconductor technology has improved both in terms of performance capability and cost. Technology like SDR (software defined radio)  have emerged from military and research and development labs.

Software defined radio is a radio that has the ability to be transformed through the use of software or re-definable logic. This radio is able to take advantage of digital processing. To do that, the traditional analog signal must be converted to and from the digital domain. This is accomplished using analog-to-digital (ADC) and digital-to-analog converters (DAC).

What are the limits of software defined radio?
Despite the fact that an ADC or DAC connected directly to an antenna is a desirable end goal, there are issues with selectivity and sensitivity that an analog front end can remedy. The alternative to digitizing at the antenna is the use of a completely flexible analog front end (AFE) capable of translating a wide range of frequencies and bands to that which the data converters themselves can adequately process.

Software defined radio is the ideal candidate to be used for multi-carrier, single-carrier, single-band, multi- band and multi-mode transceiver.

In the case you are still asking What is software defined radio .. we can say it is implementing a receiver together with the  transmitter) in a software. Such software defined radio will perform much better than an analog one, because filters can be made much closer to ideal (steep slopes, high rejection of unwanted RF signal. Do not forget also the advanced algorithms can be implemented to do things that are not so easy in analog hardware (e.g., automatically tuned notch filters).

1) Design Flexibility