AdvancedTopic 98 of 101Signals, Control & Comms
Software-defined radio
Radios implemented mostly in software for flexibility.
In depth
SDR implements modulation, filtering and demodulation in software on general-purpose processors, FPGAs or DSPs after wideband ADC/DAC; reconfigurable for multiple standards. Platforms: USRP, RTL-SDR, GNU Radio. Enables rapid prototyping, cognitive radio and 5G baseband.
Key points
- Direct-conversion receivers
- Sampling bandwidth
- Processing latency
ExampleAn RTL-SDR dongle plus GNU Radio can receive FM broadcast and ADS-B.
What is Software-defined radio?
Radios implemented mostly in software for flexibility.
Why is it important to understand software-defined radio?
Software-defined radio moves radio processing into software, which gives flexibility to change standards and functions without new hardware.
What is the advantage of SDR?
The same hardware can run different protocols by changing software, which reduces cost and speeds development.
What limits SDR?
The analogue front end, the sampling rate and processing power set the bandwidth and performance, so they must be chosen carefully.
How is Software-defined radio used in practice?
Typical applications include building a receiver that can tune many bands with one board, testing a new modulation scheme before fixing it in hardware and monitoring the radio spectrum with a general purpose receiver.
What should I learn before Software-defined radio?
Study "Radar basics" first (topic 97 of 101 in Signals, Control & Comms). It covers the groundwork this topic builds on.
What are the key points of Software-defined radio?
Direct-conversion receivers. Sampling bandwidth. Processing latency.
Can you give an example of Software-defined radio?
An RTL-SDR dongle plus GNU Radio can receive FM broadcast and ADS-B.
What comes after Software-defined radio?
The next topic is "Network information theory and 6G", which builds directly on this one.
How difficult is Software-defined radio?
It is classed as Advanced in Signals, Control & Comms (topic 98 of 101). It is an advanced topic. It assumes you are comfortable with the intermediate topics in Signals, Control & Comms.