Ask HN: How much digital data could fit on a standard vinyl LP?
8 comments
Related: Booting from a vinyl record (http://boginjr.com/it/sw/dev/vinyl-boot/)
I love this!
Usually the top performing codec is OFDM or something similar, which is a lot like FSK with a huge number of channels.
You have to equalize that signal to match the capabilities of the channel. I think you can record well past 18k bandwidth with vinyl, this was used to encode quad audio in the classic rock era. That part of the signal rubs off when you play it unfortunately.
You have to equalize that signal to match the capabilities of the channel. I think you can record well past 18k bandwidth with vinyl, this was used to encode quad audio in the classic rock era. That part of the signal rubs off when you play it unfortunately.
Cheers for the heads up about OFDM, I hadn't heard of that before! I wonder if that 18 kHz I've heard is per channel ie the sum and difference channels are both 18 kHz?
Napkin math, could be wrong:
At 18kHz per channel and 70dB S/N the Shannon-Hartley theorem suggests the maximum channel capacity of a vinyl record is around 50k bits per second. Note that SH is an ideal metric
So if your LP has 23 minutes of playtime you've got around 69Mbit of storage.
At 18kHz per channel and 70dB S/N the Shannon-Hartley theorem suggests the maximum channel capacity of a vinyl record is around 50k bits per second. Note that SH is an ideal metric
So if your LP has 23 minutes of playtime you've got around 69Mbit of storage.
Is that 23 minutes per side?
Cooper95(1)
As vinyl records are fundamentally analogue we need a digital modulation technique, apparently vinyl has about 18 kHz of bandwidth available so perhaps we could employ several frequency-shift keying channels? Could we do better than audio frequency shift keying^1 since vinyl records have more bandwidth available than the phone lines this is used on?
https://en.wikipedia.org/wiki/Frequency-shift_keying#Audio_frequency-shift_keying