3 ms·
> To store a "0" data bit, there will only be one peak in an 8us window; to store a "1" data bit there will be two peaks. Looks to me like this is just FSK (ht
by bigbillheck 5y ago
> To store a "0" data bit, there will only be one peak in an 8us window; to store a "1" data bit there will be two peaks.
Looks to me like this is just FSK (https://en.wikipedia.org/wiki/Frequency-shift_keying https://en.wikipedia.org/wiki/Frequency-shift_keying), and if so that's great because it means you can use techniques more sophisticated than the ones in that post, which in turn means that you have a chance to go after more 'unreadable' discs.
- scarybeast 5y agoDo you have any recommendations for any particular techniques or software? I'd gladly try them.
- bigbillheck 5y agoThe classical approach is a matched filter. Here's some references: https://www.rfcafe.com/references/articles/wj-tech-notes/fsk-signals-demodulation-v7-5.pdf https://www.rfcafe.com/references/articles/wj-tech-notes/fsk... http://edge.rit.edu/content/P09141/public/FSK.pdf http://edge.rit.edu/content/P09141/public/FSK.pdf There's lots of matlab code floating around out there, if you're willing to try gnuradio that'll work (for example: https://nccgroup.github.io/RFTM/fsk_receiver.html https://nccgroup.github.io/RFTM/fsk_receiver.html), and this looks promising: http://www.whence.com/minimodem/ http://www.whence.com/minimodem/ ETA: Audacity might be able to do it too : https://www.youtube.com/watch?v=tKNNnbgoGdI https://www.youtube.com/watch?v=tKNNnbgoGdI
- marcan_42 5y agoThis is how I've done it in the past, seems to work quite well on your wav file :) https://colab.research.google.com/drive/1Zvb6bQfC3thc5-39expyBkIg-3oHWEhF?usp=sharing https://colab.research.google.com/drive/1Zvb6bQfC3thc5-39exp...