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Oona (windytan)
@
windyoona
Finland
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Programmer interested in signals and sound waves // blog: windytan.com
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5.191
Tweetovi
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182
Pratim
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12.604
Osobe koje vas prate
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Oona (windytan)
@windyoona
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1. velj |
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Just listening to local UHF around 450 MHz and maybe improving an 8-channel parallel NFM receiver program :)
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Oona (windytan)
@windyoona
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26. sij |
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It could be a fun experiment! Much more bandwidth there
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Oona (windytan)
@windyoona
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26. sij |
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It is indeed, I see the point now. Could be worth thinking about. I try to get around the bin alignment problem by using peak interpolation. It works pretty well for high SNR signals even though there's only around 40 FFT bins for the whole color range.
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Oona (windytan)
@windyoona
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26. sij |
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Sorry, a clarifying question: what is the context of FSK here? Or are you referring to the video FM?
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Oona (windytan)
@windyoona
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26. sij |
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The right border can look messy in some fast YUV modes. Idea: optional zoom-in to hide 1% overscan (only the top-right corner shown here) pic.twitter.com/WWwAMAc6NO
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Oona (windytan)
@windyoona
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26. sij |
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The pictures are static.
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Oona (windytan)
@windyoona
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26. sij |
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Slow-scan television is an amateur radio picture transmission method.
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Oona (windytan)
@windyoona
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26. sij |
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Moderate levels of noise could optionally be removed by adapting the FFT windowing function to SNR (based on F2DC's article in the May/June 2003 issue of QNX: "Some Thoughts on Real-Time SSTV Processing") pic.twitter.com/XZ2T13MNzA
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Oona (windytan)
@windyoona
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26. sij |
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Yes, it reads WAV files or any other audio format. Currently it requires that the signal starts with a Robot header, but I'm also dreaming of a sync-only detector that could start in the middle of an image.
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Oona (windytan)
@windyoona
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26. sij |
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Experimental command-line SSTV decoder used with iTerm2's imgcat pic.twitter.com/MI4LkSi0ac
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Oona (windytan)
@windyoona
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26. sij |
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Beautiful
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Oona (windytan)
@windyoona
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25. sij |
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It's difficult to say based on the spectrogram alone. It could also be another similar protocol specifically designed for satellite use. But indeed, I don't have a lot of experience with satellite signals.
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Oona (windytan)
@windyoona
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24. sij |
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It’s beautiful!
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Oona (windytan)
@windyoona
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15. sij |
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I did try this with a stereo photo pair and color SSTV earlier. There was a perceptible stereo effect in the audio but mostly the colors just all sounded shifted to the right wrt the sync signal. So a slight disappointment. Maybe a simple line drawing would sound more fun.
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Oona (windytan)
@windyoona
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15. sij |
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The reason I think this would sound interesting is that the depth illusion comes from the horizontal offset of corresponding objects in the two images. In a radiofax transmission, a horizontal offset corresponds to a time delay. We can use inter-aural delays to hear directions.
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Oona (windytan)
@windyoona
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15. sij |
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Oona (windytan)
@windyoona
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15. sij |
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Shower thoughts: If you converted a stereoscopic image pair into two radiofax transmissions so that the left image was played to the left ear and vice versa, could the inter-aural time differences tell your brain something meaningful about 3D depth in the image?
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Oona (windytan)
@windyoona
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11. sij |
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Unsure if that's right. I'm interpolating between impulse responses, to put it simply. Actual science people are better at explaining it, see for example section 2.3 here, from page 14 onward. researchgate.net/publication/24…
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Oona (windytan)
@windyoona
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10. sij |
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It’s true though
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Oona (windytan)
@windyoona
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9. sij |
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what even
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