What does SDR stand for?

SDR stands for Software Defined Radio, which refers to a radio communication system where traditional hardware components are replaced or supplemented by software. In SDR, the modulation, demodulation, filtering, and other signal processing tasks are handled by software running on a computer or dedicated hardware. This allows for greater flexibility and adaptability in terms of the types of signals that can be processed and the frequencies that can be tuned.

One of the main advantages of SDR technology is its ability to easily upgrade or reconfigure the system through software rather than requiring new hardware. For example, users can change the software to allow for different communication protocols or frequency bands without needing to replace the radio's physical components. This adaptability is particularly beneficial in applications such as emergency communication, military operations, and experimental radio.

The other options do not accurately reflect the concept of SDR, as they suggest either incorrect terminologies or a misunderstanding of the core principles of defining radio systems.