Hi Russ,
Yes. In the previous reference, there is no example for overlap-add. A sine/cosine framework is a relatively simple one for OLA and fulfills the necessary requirements. In the case of audio coding, various filterbanks with different types of windows have been designed for 'perfect reconstruction', and even window switching. Please refer to Bosi for a more thorough treatment. Best, Eric Z On Wed, Jun 24, 2020, 3:44 PM Russell Wedelich <wedel...@gmail.com> wrote: > Respectively Eric, I think you may be confusing two different use cases > for windows. Your recent reference is referring to constructing FIR filters > via the Windowing method of ideal brickwall filters. This is different from > a frequency domain convolution implementation of an FIR filter (which may > or may not explicitly apply a smooth window) which as far as I can tell is > the origin of this part of the discussion. > > -Russ > > On Wed, Jun 24, 2020 at 2:28 PM Zhiguang Eric Zhang <zez...@nyu.edu> > wrote: > >> not to beat a dead horse but you get more stats here: >> >> https://www.dspguide.com/ch16/1.htm >> >> (c) shows that the Blackman has a better *stopband attenuation*. To be >> exact, the stopband attenuation for the Blackman is -74dB (∼0.02%), while >> the Hamming is only -53dB (∼0.2%). Although it cannot be seen in these >> graphs, the Blackman has a *passband ripple* of only about 0.02%, while >> the Hamming is typically 0.2%. In general, the Blackman should be your >> first choice; a slow roll-off is easier to handle than poor stopband >> attenuation. >> >> On Wed, Jun 24, 2020 at 12:17 PM Zhiguang Eric Zhang <zez...@nyu.edu> >> wrote: >> >>> https://community.sw.siemens.com/s/article/the-gibbs-phenomenon >>> >>> "*Addendum #2: Analog to Digital Converters* >>> >>> Sometimes there is confusion about a Successive Approximation Register >>> (SAR) versus Sigma-Delta analog to digital converters and Gibbs phenomenon. >>> Many Sigma-Delta converters have sharp anti-aliasing filters which prevent >>> alias errors. But these sharp filters are not inherent to Sigma-Delta >>> converters, any type of filter can be used. >>> >>> Using a filter with a gradual roll-off with any analog to digital >>> converter reduces or eliminates the Gibbs phenomenon. The effect of the >>> filter should not be confused with the type of analog to digital converter. >>> In fact, a lowpass filter can even be used after the acquisition on a >>> digitized signal containing Gibbs to remove the phenomenon." >>> >>> >>> seems like your LPF in your ADC should 'remove' this artifact to >>> undetectable levels if you're sampling from an analog source, but in >>> software, it just depends on your windowing >>> >>> On Wed, Jun 24, 2020 at 11:47 AM Zhiguang Eric Zhang <zez...@nyu.edu> >>> wrote: >>> >>>> here: >>>> >>>> https://community.sw.siemens.com/s/article/the-gibbs-phenomenon >>>> >>>> "*The Gibbs Phenomenon* >>>> >>>> [image: User-added image] >>>> >>>> To describe a signal with a discontinuity in the time domain requires >>>> infinite frequency content. In practice, it is not possible to sample >>>> infinite frequency content. The truncation of frequency content causes a >>>> time domain ringing artifact on the signal, which is called the “Gibbs >>>> phenomenon”." >>>> >>>> >>>> >>>> in order to eliminate the ringing artifact altogether, you'd need a >>>> hell of an ADC, one that doesn't exist today (nor shall one ever exist to >>>> eliminate the artifact). it is part sampling theory and there's no way >>>> around it. >>>> >>>> On Wed, Jun 24, 2020 at 11:45 AM Corey K <corey...@gmail.com> wrote: >>>> >>>>> You don't have to sample the STFT that often. In fact block based FFT >>>>> convolution uses non-overlapping blocks on the input (although the output >>>>> windows do overlap). Anyway, I digress... >>>>> >>>>> On Wed., Jun. 24, 2020, 1:06 p.m. Zhiguang Eric Zhang, <zez...@nyu.edu> >>>>> wrote: >>>>> >>>>>> It's not just about zero-padding. Say you could sample the signal >>>>>> and window at, say, fs, but why the hell would you want to window at fs? >>>>>> At any rate, if you look at the Hamming window, the ringing artifact is >>>>>> rather negligible. >>>>>> >>>>>> >>>>>> On Wed, Jun 24, 2020, 11:15 AM STEFFAN DIEDRICHSEN < >>>>>> sdiedrich...@me.com> wrote: >>>>>> >>>>>>> Phew, thank you for confirming that! We use it in several products. >>>>>>> >>>>>>> Cheers, >>>>>>> >>>>>>> Steffan >>>>>>> >>>>>>> On 24.06.2020|KW26, at 17:07, Corey K <corey...@gmail.com> wrote: >>>>>>> >>>>>>> But the end result is that we can perform filtering using STFT >>>>>>> filterbanks just fine, there are no artifacts. >>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>>> dupswapdrop: music-dsp mailing list >>>>>>> music-dsp@music.columbia.edu >>>>>>> >>>>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.columbia.edu_mailman_listinfo_music-2Ddsp&d=DwICAg&c=slrrB7dE8n7gBJbeO0g-IQ&r=w_CiiFx8eb9uUtrPcg7_DA&m=yZ5_ZeKmy3sswDToK2aeereR1JOnaPvsIiQIFV61n3s&s=CCun327jvXB9hliV_3DHUKwKgRVRi8xdsZyOtqHPAfw&e= >>>>>> >>>>>> _______________________________________________ >>>>>> dupswapdrop: music-dsp mailing list >>>>>> music-dsp@music.columbia.edu >>>>>> https://lists.columbia.edu/mailman/listinfo/music-dsp >>>>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.columbia.edu_mailman_listinfo_music-2Ddsp&d=DwMFaQ&c=slrrB7dE8n7gBJbeO0g-IQ&r=w_CiiFx8eb9uUtrPcg7_DA&m=s95xHGQ6LAiwB1zMrc7VeayM-fKr760Or7TCJlScQfc&s=BZnqxM9Q-zTNeu_a0p-Ga9nEXBm6SL6VKtfeCmHRL80&e=> >>>>> >>>>> _______________________________________________ >>>>> dupswapdrop: music-dsp mailing list >>>>> music-dsp@music.columbia.edu >>>>> >>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.columbia.edu_mailman_listinfo_music-2Ddsp&d=DwICAg&c=slrrB7dE8n7gBJbeO0g-IQ&r=w_CiiFx8eb9uUtrPcg7_DA&m=s95xHGQ6LAiwB1zMrc7VeayM-fKr760Or7TCJlScQfc&s=BZnqxM9Q-zTNeu_a0p-Ga9nEXBm6SL6VKtfeCmHRL80&e= >>>> >>>> _______________________________________________ >> dupswapdrop: music-dsp mailing list >> music-dsp@music.columbia.edu >> https://lists.columbia.edu/mailman/listinfo/music-dsp > > _______________________________________________ > dupswapdrop: music-dsp mailing list > music-dsp@music.columbia.edu > https://lists.columbia.edu/mailman/listinfo/music-dsp
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