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Table of Contents
GNURadio Tips and Notes
Introduction
GNURadio is really cool. But the documentation is quite poor. With that in mind here are some random, unorganised tips and useful flowgraphs that will get you started and provide a base for your own projects.
Mark MM3IIG
Using Baseband I/Q Recordings
Depending on the specifics of your recording you may need to change bits of this. You’ll want to use a WAV file sync, set the channels to two, and then immediately convert from float to complex to do useful things with the data. Then you’ll want a throttle block to set your desired sample rate. If you have recordings in a format other than 16-bit stereo you may need to add extra conversion steps, or convert your input file first with other software.
If your chosen signal is in the middle of the baseband, you’re done! If it isn’t, you will need to “tune in” to the signal with a Frequency Xlating FIR or FFT Filter first.
Adding, Subtracting, and Multiplying Signals
Are you modulating a signal onto another signal? Such as modulating audio data onto a carrier tone? You want multiply for this.
Are you merging signals together to make a final product to transmit/save/whatever? Such as merging an audio signal with an RDS data signal? You want add in that case.
You barely seem to need subtract unless you’re doing difference-based stereo like with Broadcast FM, so there’s nothing interesting to say about it here. Yet.
Useful Flowgraphs
Add a list of useful GRCs with explanatory text here. You can build your own projects off these.
To be added:
- AM Modulation
- AM Demodulation
- NFM Modulation
- NFM Demodulation
- QPSK Modulation
- QPSK Demodulation
- BPSK Modulation
- BPSK Demodulation