VLF

Current-code revision note This revision supersedes the older 1 MHz / TIM3-TRGO timing description. The current firmware revision was checked against main(5).c. The actual timing architecture is: PA0 / 1 MHz ──► TIM5_CH1 ──► TIM5 counter / timestamp PA3 / GNSS PPS ─────────────► TIM5_CH4 capture PA6 / 1 MHz ──► TIM3_CH1 ──► reset ──► TIM3_CC4 ──► ADC1/2/3 In particular, TIM3 TRGO is not used for the ADCs. TIM5 does not generate the ADC sampling clock; it counts a separate external 1 MHz timing signal on PA0. ...

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. ...