555 Super-Regenerative IF HF Spectrum Analyser

This is another of those crazy ideas that have been rolling around in my head for a while now. I have previously used super-regenerative circuits as logarithmic detectors, and built super-regenerative super-heterodyne receivers - it wasn’t a huge leap to build a swept front-end and turn the combination into a simple spectrum analyser. The recent announcement of a 555 Contest by Chris Gammell and Jeri Ellsworth had me playing with 555 circuits and this was all the encouragement I needed to finally go ahead and do it. The end result is a toy SA adapter for your CRO, but is still useful instrument (and it fits in an Altoids tin).”


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