Signal Processing

WIP Programmable signal generator with GNSS-checked timing The idea I want to build a programmable function generator for my lab. The basic architecture is: STM32H743ZI → high-speed DAC → analog output with a u-blox GNSS receiver providing a long-term timing reference. The first target is relatively simple: generate a clean sine wave up to at least 10 MHz. The exact output stage and reconstruction filter still need to be designed. I chose the STM32H743ZI for a very practical reason: I already have a NUCLEO-H743ZI board sitting on my bench. ...

2 ch Simultaneous time-domain, spectrum, and waterfall monitoring with GPS-disciplined acquisition and unattended recording Overview VLFRecorder is a Windows desktop application for continuous, unattended acquisition and monitoring of Very Low Frequency signals at lightning detection stations. The application grew from a single-channel proof of concept into a dual-channel real-time acquisition system with: continuous two-channel recording; hardware-disciplined sample timing; GPS/PPS synchronization; real-time time-domain and spectral visualization; scrolling waterfall spectrograms; measurement cursors; GPS-aligned session management; acquisition and connection error logging; automatic post-processing and sferic extraction. The software is used for day-to-day operation of the station’s data acquisition hardware, so the primary design constraint is not simply displaying data quickly. The acquisition pipeline must continue receiving samples while visualization, GPS parsing, file I/O, and analysis are running independently. ...

2 sites Digital twin system for TEC, Doppler and other measurements Overview IONOSPHERE_PRO is a web dashboard and processing pipeline for a small network of ground stations that measure ionospheric total electron content (TEC) by tracking the coherent dual-frequency beacon transmitted by the Ionosfera-M satellite pair. Each station records raw IQ samples at 150 MHz and 400 MHz during a satellite pass; the backend turns those recordings into phase and TEC curves; the frontend presents all of it as a live map with a per-station history of processed sessions. ...