How does Software-defined Radio (SDR) work?

Updated January 2021

Most of us are familiar with communication devices such as AM/FM radios, Smart phones and Two-way radios. The radios within these devices are comprised of hardware in the form of electronic circuits.

AM/FM Radio Receiver

All the hardware in an AM/FM radio is designed for one main task only – and that is to process AM/FM signals. Now if you want to process more than one type of signal, you will either need multiple radios, one for each type of signal. Or you will need a system that includes dedicated hardware (integrated circuits for instance) for each type of signal protocol. However there is a practical physical limit to how many radios can be combined into one.

Many radio systems can be combined into one using different integrated circuits for each protocol

Software-defined radio simplifies this approach considerably. In a SDR, the processing is done in both hardware and software. SDR uses a common wideband radio front end and a software processor to process signals.

Software-defined radio simplifies communication systems

Software provides the flexibility to process many different types of signals. The user can then use one SDR device to process all kinds of signals from FM to 4G/LTE. In fact there is no limit to the number or type of signals that can be processed in software. This is the power of Software-defined Radio! SDR has grown significantly in popularity. 20 years ago there were only a couple of SDRs on the market. Today however there are over a hundred different SDR transmitters, receivers and transceivers. Many options to choose from depending on your requirements.