Hmm, not so sure. He produced a digital signal, who’s spectrogram happened to be an image, and then played that digital signal to a bird. Dunno if a analogue spectrogram really even makes sense as a concept. The only analogue part of the chain would be the birds vocalisations, right?
gozz@lemmy.world 4 days ago
Not to be a wet blanket, but every time this comes up I get annoyed by some factual inaccuracies in the articles about this. It is not digital! He drew an image on a computer, but converted it to an analogue spectrogram to store on the bird. That’s neat as hell, but it’s not digital. The image that he got back was slightly corrupted.
Now I would be fascinated to see a follow-up seeing if you can actually modulate a digital signal and have is survive a round trip through the bird bit-for-bit accurate. I suspect in reality it would be much lower data rate, but definitely not nothing!
abruptly8951@lemmy.world 4 days ago
gozz@lemmy.world 3 days ago
The whole sequence is:
- Digitally synthesized spectrogram (lossless)
- Played through a DAC and speaker to produce an analogue signal (lossy)
- Heard by the bird (analogue, lossy)
- Reproduced by the bird (analogue, lossy)
- Captured by an ADC as a digital audio signal (lossy)
- Spectrum-analysed to observe a similar (but corrupted) reproduction of the shape in the PNG
To be transferring digital information, we would instead need to modulate and demodulate the digital signal (exactly like an old modem) so that the analogue corruption does not affect the digital signal:
- Image file (lossless)
- Bit stream (lossless)
- Analogue modulation of bit stream played through DAC (lossy)
- Heard by the bird (lossy)
- Reproduced by the bird (lossy)
- Demodulated to recover exact bit stream despite distortion (lossless,)
- Decode bit stream to recover original image file, bit-for-bit perfect
I extremely doubt that this bird is capable of 2MB/s. For reference that would make it 280+ times fast than dialup, and barely slower than ADSL. This setup is basically just using the bird instead of a telephone line.
CookieOfFortune@lemmy.world 3 days ago
- Played through a DAC and speaker to produce an analogue signal (lossy)
Analogue modulation of bit stream played through DAC (lossy)
These steps are literally the same thing. You’re converting some data into sound for the bird to hear.
gozz@lemmy.world 3 days ago
Yes, the near-identical sentences (only drawing a distinction between the processes where one exists) would indicate that. The “heard by the bird” and “reproduced by the bird” steps were also the same. But this is necessary context to make clear the digital data (“bit-stream”) that is being modulated into the signal.
It is far from “exactly the same”. The similarity is only in that both go through the same analogue channel. The entire point is that the modulated signal can be reconstructed exactly, while the spectrogram cannot.
Underwaterbob@sh.itjust.works 4 days ago
The sound from the speakers he must have used was also “analog”. Sound - defined as a pressure wave through a medium - can’t be digital. Though the difference between analog and digital kinda loses meaning in cases like this.
CookieOfFortune@lemmy.world 4 days ago
Every signal is ultimately analog. Voltage along a wire, sound, light, the world is analog and it all needs to be converted into our concept of digital (which is typically binary values).
CookieOfFortune@lemmy.world 4 days ago
By your definition nothing can be digital since the world is analog. Even the bits in your CPU are voltages in transistors. As such, every real life signal can be distorted.
Lifter@discuss.tchncs.de 3 days ago
The point with digital transfers is that you round it back to either 0 or 1, hoping that no bits are distorted enough to have any loss at all.
gozz@lemmy.world 3 days ago
Exactly. Digital logic, when implemented in analogue, generally have to have forbidden zones where a signal in that range is considerer invalid. Regardless of implementation, digital is about the discretized logic of the system. That is explicitly the whole point of digital: Minor analogue distortion does not change the information content of the signal unless it is so bad as to flip a bit.
CookieOfFortune@lemmy.world 3 days ago
This isn’t true in the general case. In the real world, you can have all kinds of distortions: random noise, time shifts, interference from other signals, etc.
You don’t usually see the effects of these because the protocols are designed with the communication channel characteristics in mind in order to reproduce the original signal.
Using birds is just another communication channel with its own distortion characteristics.
CookieOfFortune@lemmy.world 3 days ago
That’s not really how it works in the real world. Usually you have both bandwidth and noise constraints.
Sure you can send something like a square wave but this isn’t practical for real communication channels. Typically you’re sending many sine waves in parallel with multiple amplitudes and phase offsets to represent a sequence of bits (QAM). Then on top of that you’d encode the original data with both a randomizer (to prevent long runs from looking like nothing) and error correction. So usually the system can handle some level of distortion.
What you’re hoping is that by the time the data reaches the user (really, Layer 3), all the errors have already been handled and you never see any issues.
The bird is just another type of noisy channel with its own distortion characteristics.
Lifter@discuss.tchncs.de 3 days ago
You are not addressing my critique of your statement, just piling on a bunch of useless extra knowledge just so that you can feel superior.
socsa@piefed.social 3 days ago
The point is that at the physical layer you still have a well defined log likelihood test to produce digital information. That's why QAM lasted so long even though it is not power efficient - because it has an analytical likelihood function.
This is the boundary between digital and analog communications. Since he did not use a digital modulation scheme, this would be a form of analog comms
Regrettable_incident@lemmy.world 3 days ago
I dunno how you’d use check digits with a bird, but this seems the obvious way to deal with corruption. Or maybe give the bird more treats.