John K. Boyle

Weekly Catchup

11 Aug 2014 - La Jolla, CA

Thing 1

view from my window

I see a lot of eucalyptus trees now. I’ve moved from sunny Portland, to sunny San Diego, CA.

Thing 2

Xiph.Org is the group behind the FLAC, Ogg Vorbis, and Theora multimedia formats. Recently they released two videos about the basics of digital media (from a signal processing point of view). I highly recommend watching both.

Xiph.Org Video

Thing 3

Over at windytan’s blog, absorptions, is an article about basic audio transmission with a laser. She used single-side-band (SSB), frequency-modulated audio for transmission, and demodulated the received signal with hardware. I’m not too familiar with frequencey modulation, and wanted to hear the modulated signal (at 6kHz), but she didn’t provide audio, nor the code for demodulating the same audio file.

Starting from her script, I added modulation and demodualtion of a different file using the same method. I put the code and an audio file up on Github in my one-off project collection repository prac (as in “practice”).