IP: GNU Radio

[David Farber <dave () farber net>]

http://www.gnu.org/software/gnuradio/

Introduction

GNU Radio is a collection of software that when combined with minimal 
hardware, allows the construction of radios where the actual waveforms 
transmitted and received are defined by software. What this means is that 
it turns the digital modulation schemes used in today's high performance 
wireless devices into software problems.

What is a Software Defined Radio?
Joe Mitoloa says, "A software radio is a radio whose channel modulation 
waveforms are defined in software. That is, waveforms are generated as 
sampled digital signals, converted from digital to analog via a wideband 
DAC and then possibly upconverted from IF to RF. The receiver, similarly, 
employs a wideband Analog to Digital Converter (ADC) that captures all of 
the channels of the software radio node. The receiver then extracts, 
downconverts and demodulates the channel waveform using software on a 
general purpose processor." [1]

For our purposes, on the receive side, the idea is to get a wide band ADC 
as close to the antenna as is convenient, get the samples into something we 
can program, and then grind on them in software.

Can you give me an example?

To get a better idea of what we're talking about, please see the screen 
shots and examples. They range from playing a sine wave out a speaker, a 
single channel FM receiver, a display of the real time Fourier transform of 
the signals from a high speed analog to digital converter, to an 
application that receives two broadcast FM stations at the same time from 
the same input.

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