[fps-hero]

Very interesting! Thanks for sharing.

It’s very frustrating that the tried and true method of sampling comparators has become prohibitively expensive due to niche parts.

I suspected that the ST HRTIMER would be a good candidate for replacing the delay line components, with the benefit of synchronisation for free. Good to see it works!

The diode bridge sampling and verification is the “hard part”. My motivation was for wanting to make a TDR was lack of equipment required to measure the signals required. Ironically, it’s the very equipment you need decent equipment to verify a TDR is working correctly. Most existing designs attempt to replicate old sampling bridges that use exotic unobtainable diodes. If you stray from the tried path, it’s up to you to verify performance, so there is some valuable insight here.

I liked reconstructing the signal using a spectrum analyser, very clever idea.