How does an FIR filter work in GNU Radio
Admin
An FIR filter (Finite Impulse Response filter) in GNU Radio works by applying a weighted sum of a finite number of input samples to produce each output sample. Let’s break…
Software
How could I create the equivalent of the FM demodulator block in GNU Radio, if the block did not exist?
FM demodulation looks mysterious in GNU Radio because it’s one tidy block… but under the hood it’s actually very simple. FM is just information encoded as changes in instantaneous frequency.…
Flowchart and figures from Communication systems with GNU Radio book
https://gitlab.com/gnuradio_book/flowcharts
In GNU Radio there is an AM demod block. If this wasn’t there what processes would be required to achieve same function?
AM demod looks simple on the surface, but under the hood it’s doing a couple of neat little tricks. If the built-in AM demod block vanished overnight, you’d rebuild it…
When writing an GNU Radio flowgraph for AM radio why must radio signal Input be multiple by fixed signal source before filtering?
Ahhh yes, welcome to the “why are we multiplying things?” club 😄 — this is actually the heart of how a radio works. Short answer:You multiply the incoming RF signal…
Creating 3D images with ezRA and Rinearn 3D, and with H-Line 3D
https://www.astronomy.me.uk/wp-content/uploads/2026/02/How-to-run-Alex-Pettit-3D-project-using-Ted-Cline-scripts-ezRA-191124.docx https://www.astronomy.me.uk/wp-content/uploads/2026/02/Alex-Pettit-Rinearn3D_QuickSettings02-041225.docx https://www.astronomy.me.uk/wp-content/uploads/2026/02/Full-Instructions-for-creating-4D-images-in-ezRA-Rinearn3D-250125@2330.docx https://www.astronomy.me.uk/wp-content/uploads/2026/02/Instructions-from-Ted-Cline-on-using-ezCol-data-with-Rinearn3D-RinearnHow241021a.pdf
How do switch blocks and selector blocks in GNU Radio work?
These two get mixed up all the time in GNU Radio because they sound similar but solve slightly different problems. I’ll explain them intuitively first, then a bit more technically,…
I am looking for a GNU Radio flowgraph on Github or elsewhere that shows me how to incorporate ability to choose between SDRs whilst running the program.
Here are some open-source GNU Radio flowgraphs / projects on GitHub that you can study or adapt when you want to choose between different SDR hardware sources (e.g., RTL-SDR, USRP,…
QT GUI Vector Sink in GNU Radio – does it show offset of the signal from centre?
Short answer: no — not by itself 🙂 The QT GUI Vector Sink does not inherently show frequency offset from centre. It just plots whatever numbers you feed into it,…
In GNU Radio how can I make positive complex number negative?
Nice, this is a very GNU Radio–ish question 🙂 In GNU Radio, a complex number doesn’t have a “positive” or “negative” sign the way a real number does. If you…