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by pja
1476 days ago
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You are very insistent on proving yourself right by changing the topic to one where your assertions are correct instead of dealing with the discussion that everyone else was having. It’s a neat rhetorical trick, but kind of annoying in a context where everyone else is just trying to have a constructive discussion. In this context, we were talking about digital audio & the perception thereof by human listeners. Spread spectrum signal processing techniques are not relevant. Driving the noise floor down to the quantum limit by using liquid helium & a bunch of other abstruse techniques is not relevant. The fact that GPS signals are below the noise floor in their radio spectrum is, once again, not relevant. Do you argue like this in all your interactions with other people? |
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Actually, this thread was on sampling theory and whether or not Nyquist perfectly recreated original signals. The only mention of anything about human perception in the chain you're replying to is me writing that good engineering can push errors outside human hearing, while pointing out that it is not the original signal. All the other posts in the thread you claim is about human perception are not about human perception. They're about signal reconstruction with one mention of how that applies to hearing.
>Do you argue like this in all your interactions with other people?
No, most of my friends don't make incorrect claims then double down on them when better information is pointed out. They also don't tend to claim an entire conversation is about a different topic than it was.
You: "Up to the Nyquist limit, a digital signal will completely recreate the original signal". No, as explained.
You: "Digitisation does not result in square wave output anywhere in the output chain" - again false, even for audio, as explained above. Thinking that output is a nice set of pure sine waves making the original band limited (which is also an approximation) leads people to flawed thinking. Realizing the how and why of what actually comes out is useful.
You imply pushing things below a noise floor makes them indistinguishable from noise - this isn't true in general, and is not even true in audio. There are even audio products that use signaling below the noise floor. Repeated misunderstanding of what a noise floor is (and isn't) is extremely useful, even in audio. The other examples were to make it clear there is useful knowledge here.
Understanding these nuances is useful for even audio to understand that reconstruction is always a design tradeoff on where you want to put the errors - and that you never are reconstructing the original signal.