[music-dsp] Did anybody here think about signal integrity

2015-06-03 Thread Theo Verelst
Hi, Playing with analog and digital processing, I came to the conclusion I'd like to contemplate about certain digital signal processing considerations, I'm sure have been in the minds of pioneering people quite a while ago, concerning let's say how accurate theoretically and practically all

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-03 Thread Ethan Duni
"Perfect" sinusoids/square waves/etc. only exist as mathematical abstractions. A good starting point would be to get a feel for what, say, the "square wave" coming out of an analog synthesizer actually looks like - the noise floor, the distribution of harmonics, frequency jitter, under/overshoot, e

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-03 Thread Ethan Duni
Also a good starting place for beginners are the xiph show-and-tell videos (probably been posted here before, but whatever): https://xiph.org/video/vid2.shtml E On Wed, Jun 3, 2015 at 3:05 PM, Ethan Duni wrote: > "Perfect" sinusoids/square waves/etc. only exist as mathematical > abstractions.

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-05 Thread Stefan Stenzel
Theo, Any continuous function bandlimited to frequencies < fs/2 is completely determined by its samples. That’s the essence of the sampling theorem, which answers all your questions. Stefan > On 03 Jun 2015, at 22:47 , Theo Verelst wrote: > > Hi, > > Playing with analog and digital processi

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-05 Thread gwenhwyfaer
Well, bandlimited to a bandwidth < fs/2 (but the distinction isn't useful for audio), and given perfect reconstruction circuitry. But as far as I can gather, Theo's concern is "what happens when, as is inevitable in practice, the reconstruction circuitry is imperfect?" And that is an interesting qu

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread vadim.zavalishin
Hi, I was asking a very similar question about one year ago on this list in the context of the BLEP theory. The point is that the samping theorem is incomplete compared to how we would like to (and do) use it in the signal processing. The sampling theorem applies only to the class signals whi

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread Victor Lazzarini
Not sure I understand this sentence. As far as I know the FT is defined as an integral between -inf and +inf, so I am not quite sure how it cannot capture infinite-lenght sinusoidal signals. Maybe you meant something else? (I am not being difficult, just trying to understand what you are trying t

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread Vadim Zavalishin
If you try to take the Fourier transform integral of a exp(j*omega_0*t), it will not converge in the sense, how an improper integral's convergence is usually understood. You will need to employ something like Cauchy principal value or Cesaro convergence to make it converge to zero at omega!=ome

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread STEFFAN DIEDRICHSEN
IIRC, the discussion back then covered some topics like distortions created with polynomial functions, etc. Although DC isn’t a real problem in practical applications, there are many cases, which are hard to predict, if they cause aliasing. A good example is FM, which spectra can be predicted u

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread Vadim Zavalishin
The direct impact on the application can be e.g. using BLEPs (of 0th and higher orders) to antialias a sine hard sync or an exp-scale-modulated or self-modulated sawtooth (which produces exp segments), which seems to work but is lacking a firm theoretical foundation. In fact so does even the ba

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread Theo Verelst
Clearly, there's very little knowledge around the basic mathematical proofs underpinning a decent undergrad engineering course. Prisms understand fine what the Fourier transform is, and isn't. Maybe there's an interest in this: http://mathworld.wolfram.com/FourierTransformExponentialFunction.ht

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread Vadim Zavalishin
On 08-Jun-15 15:06, Theo Verelst wrote: Clearly, there's very little knowledge around the basic mathematical proofs underpinning a decent undergrad engineering course. Prisms understand fine what the Fourier transform is, and isn't. Maybe there's an interest in this: http://mathworld.wolfram.com/

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread Sampo Syreeni
On 2015-06-08, vadim.zavalishin wrote: The sampling theorem applies only to the class signals which do have Fourier transform, separating this class further into bandlimited and non-bandlimited. However, it doesn't say anything about the signals which do not have Fourier transform. Correct.

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread Ethan Duni
>If you try to take the Fourier transform integral of a exp(j*omega_0*t), it will not >converge in the sense, how an improper integral's convergence is usually understood. >You will need to employ something like Cauchy principal value or Cesaro convergence >to make it converge to zero at omega!=ome

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread Ethan Duni
>Now the assignment is as follows: can we, given the output signal >coming from our filter which was fed the input signal, and the filter >coefficients, compute the input signal ? Invertible digital filters are invertible, up to numerical precision. Are you wanting to talk about finite word length

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread Sampo Syreeni
On 2015-06-08, Ethan Duni wrote: But both of these are overkill for day-to-day engineering practice. Especially so, because you can treat the distributional framework as a black box. It has a certain number of rules. If you follow the rules, you'll land with a nice calculus which fully encom