Also known as: software-defined radio, SDR

Software-defined radio (SDR) moves the functions that were once fixed hardware — tuning, filtering, demodulation — into software operating on digitised IQ samples.¹ The hardware does only enough to convert a slice of spectrum into numbers.

An SDR moves tuning, filtering, and demodulation into software; the hardware just delivers IQ samples.

How it works

An SDR front-end amplifies, mixes, and digitises a band into IQ; software then does everything else. Because the differences between systems live in code, one device can decode many protocols.

Relevance to SDR

GopherTrunk is the software half of an SDR, specialised for digital trunked radio. The hardware (e.g. RTL-SDR) is almost interchangeable.

Sources

1. Software-defined radio — Wikipedia, on the architecture that moves radio functions into software. ↩

See also

• IQ data
• Analog-to-digital converter (ADC)
• Superheterodyne receiver
• RTL-SDR
• Demodulation

Learn it step by step

• What is software-defined radio?

From the blog

• SDR Internals, Part 1: What is software-defined radio?