Sin08: I hadn't heard of it either, but I can see two sources of that. The first is that input power supply disturbances that are not suppressed, will also show harmonics of that unsuppressed disturbance in the output. The other source would be source disturbances that are not suppressed because of not zero Zout. These will also created harmonics, theoretically.
I will see if I can measure them in due course, but they will be at an extremely low level, so as to the relevance???.
I will see if I can measure them in due course, but they will be at an extremely low level, so as to the relevance???.
To all, I'm not sure if this means anything. I was taking the idea that a perceptible amplitude envelope could be created using the example of two sine waves, for instance, and then looking at a more complex waveform. In fact if the difference in amplitude envelope is all due to the varying magnitude of the Gibbs ringing it probably is not audible.
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It depends. If one part or the other is way off it can be pretty bad.
Hopefully, in a good design subsystems are pretty well matched up. In that case there may be multiple things that affect fine tuning the sound. The power supply is often one of the bigger of those.
Funny enough, only when audio is involved. Otherwise, it's a 100% STEM discipline.
Those would fall under "line regulation" and "output impedance" both as a function of frequency. No "regulator linearity" involved in both.
Why draw any conclusions like 'probably is not audible? Why guess one way or the other?
It probably IS audible.
THx-RNMarsh
Scott, I have some concerns regarding on how the Hilbert transform would work in this particular discrete case; could you please pass the two time limited sines through an ideal Hilbert transform filter then check if the result z(t)=x(t)+jH(x(t))is exactly an analytic signal (no negative frequencies, or if the result is exactly in quadrature with the original)?
This is easily accomplished by manipulating the coefficients of the FFT of x(t), eliminating negative frequencies in the process, then taking the inverse transform to get z(t).
SinBoy, you are wrong. Everything that comes through will also come through with their harmonics as far as they are created. Its an amp, you know.
So you think about a voltage regulator, considered as an amplifier with (say) -100dB gain (aka "line regulation"), that will distort the input (line) perturbations superposed over DC. Now, that's a fancy metric I have never heard about, and I cannot imagine any relevance.
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Yes, that is the exact form of the Python/SciPy Hilbert() function and how it is computed. In the case of a complex music signal this could be a misapplication, I have been using it recently it with sweeps or tones to extract AM/FM effects in LP reproduction were it works very well.
Sorry, I don't know about SciPy, I thought the Hilbert transform is calculated from definition (like Mathematica does) not using directly the fundamental Hilbert transform result.
I find the result you got very strange and hard to justify on any mathematical foundation. If I remember correctly, there is a theorem that clearly states that the Hilbert transform of the product of two signals with non overlapping spectra (what you did here, I guess) is equal to the product of the Hilbert transforms of the two signals, the foundation of demodulation, otherwise the Hilbert transform is a linear operator by definition. Your result suggests that an ideal modulation/demodulation process may lead to distortions, which makes me rather uncomfortable.
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