- sigmf-toolkit
I have published a new Python package called sigmf-toolkit. It is intended to be a collection of Python tools to work with SigMF files. At the moment it only contains two tools, but I plan on adding more tools to this package as the needs arise. These tools are:
gr_meta_to_sigmf. It converts a GNU Radio metadata file with detached headers to a SigMF file. At the moment it is really simple, and it doesn’t handle capture discontinuities.- sigmf_pcap_annotate. This tool parses a PCAP file using Scapy and it adds annotations to a SigMF file for each packet in the PCAP file.
I find this
sigmf_pcap_annotatetool quite useful when comparing side by side a SigMF file in Inspectrum and a PCAP file in Wireshark to debug issues with digital communications systems. In this post I showcase how this tool can be used. - Non-coherent m-FSK BER
Yesterday I posted about how to compute the well known formula for the bit error rate of FSK with non-coherent demodulation. Later I realized that the same kind of argument can be extended to cover the case of \(m\)-FSK in which the \(m\) tones are orthogonal. The formula for this is not so well known, and I don’t recall having seen it before, although surely it is somewhere in the literature. Here I show the calculations and the closed-form expression that is obtained.
- Non-coherent FSK BER
It is well known that the formula for the bit error rate of 2-FSK using non-coherent demodulation is \(\exp(-\frac{E_b}{2N_0})/2\). However, I can never quickly find a source where this formula is derived, so I decided to figure this out and write down the derivation. I will use my post about m-FSK symbol error rate as a starting point.
- 10 years of blogging
Today marks 10 years since I wrote the first post in this blog. It was a very basic and brief post about me decoding the European FreeDV net over a WebSDR. I mainly wrote it as a way of getting the ball rolling when I decided to start a blog back in October 2015. Over the 10 years that I have been blogging, the style, topics, length and depth of the posts have kept shifting gradually. This is no surprise, because the contents of this blog are a reflection of my interests and the work I am doing that I can share freely (usually open source work).
Since I started the blog, I have tried to publish at least one post every month, and I have managed. Sometimes I have forced myself to write something just to be up to the mark, but more often than not the posts have been something I really wanted to write down and release to the world regardless of a monthly tally. I plan to continue blogging in the same way, and no doubt that the contents will keep evolving over time, as we all evolve as persons during our lifetime. Who knows what the future will bring.
I wanted to celebrate this occasion by making a summary of the highlights throughout these 10 years. I have written 534 posts, and although Google search is often useful at finding things, for new readers that arrive to this blog it might be difficult to get a good idea of what kind of content can be found here. This summary will be useful to expose old content that can be of interest, as well as serve me to reflect on what I have been writing about.
- Flip-flop timing experiments
Since watching Matt Venn‘s video about flip-flop timing, I have had at the back of my mind the idea of designing my own ASIC flip-flop and doing some simulations to measure its timing parameters. This is partly an excuse to learn how to use Magic and other VLSI design tools, and partly a good way to understand better how the numbers that appear on a flip-flop datasheet relate to what physically happens in the flip-flop.
I have now designed a flip-flop in Magic and done ngspice simulations to measure its setup, hold and output delay times. This work can be found in a flip-flop-timing repository in Github. In this post I explain how the flip-flop is designed and how the timing analysis is done.
10ghz artemis1 astronomy astrophotography ATA ccsds ce5 contests digital modes doppler dslwp dsp eshail2 fec filters freedv frequency gmat gnss gnuradio gomx hermeslite hf jt kits lilacsat limesdr linrad lte microwaves mods moonbounce noise ofdm orbital dynamics outernet polarization radar radioastronomy rust satellites sdr signal generators tianwen vhf & uhf