As part of my [[blog/Bell 103|Bell 103]] decoding, I'm trying to understand this digital signal processing (DSP) stuff in python. Why? Because I like to understand things from the ground up, so I don't want to just use something that someone else wrote (like [gr-ham](https://github.com/argilo/gr-ham/)). This is mostly because I find it easy to convince myself I understand something, but then flail when it comes to actually doing anything with it. Some things I've been reading: [Think DSP](https://greenteapress.com/thinkdsp/html/index.html) has been ok. It's more focused on audio stuff and maybe a bit too basic for me at this point. [PySDR](https://pysdr.org/) has been better. [Fourier Transforms With scipy.fft: Python Signal Processing](https://realpython.com/python-scipy-fft/) was a good blog post sized intro, but may only work because I've been thinking about the underlying stuff for a bit. It did help me figure out a problem I was having where I was looking at fft, and not rfft (and thus everything was mirrored around 0) And what I've been trying to do, is take [this sample](https://cdn.tahnok.ca/u/chu_bell_103_single_packet_unknown_type_mono_32_float.wav) and processing it a jupyter notebook. So far, I have an FFT that shows 2 faint peaks  Next up, trying to figure out how to extract data, maybe starting with the preamble