hey miller and list,
find attached a version that works beautifully. it's a dirty hack without upsampling but it works extremly well. don't ask me why, i have no idea. thanks for all the help miller, really appreciate it! and thanks for pd in general :-) cheers, simon
sinetosawtooth.pd
Description: Binary data
On Apr 27, 2014, at 8:59 PM, Simon Iten wrote: > sorry this one went off-list :-) > > > On 27 Apr 2014, at 19:05, simon <itensi...@gmail.com> wrote: > >> sure, >> >> here is the version with biquad in a subpatch with a block opject to >> upsample. probably i'm doing something wrong, i just copied from the block >> help-patch. >> >> <sinetosawtoothupsample.pd> >> >> On Apr 27, 2014, at 5:48 PM, Miller Puckette wrote: >> >>> Drat, I don't have any explanation for this... can you send me the patch >>> again? >>> cheers >>> M >>> >>> On Sun, Apr 27, 2014 at 05:44:22PM +0200, simon wrote: >>>> hmm, changing change to biquad does also not work. i mean it does as long >>>> as i don't upsample in the subpatch. as soon as i change the block object >>>> i get square instead of pulses... >>>> >>>> On Apr 27, 2014, at 3:48 PM, Miller Puckette wrote: >>>> >>>>> Actually I don't know where the change~ object is from - I've nver seen t >>>>> before. I would just use biquad~ 0 0 1 -1 0 (assuming that change~ simply >>>>> ubtracts the previous sample from teh current one as I guessed from the >>>>> patch :) >>>>> >>>>> M >>>>> >>>>> On Sun, Apr 27, 2014 at 03:40:01PM +0200, Simon Iten wrote: >>>>>> ok tried to upsample the whole thing (after the osc~) and now change~ >>>>>> does nothing anymore… it just spits out the same square wave i feed >>>>>> in…clues? >>>>>> >>>>>> >>>>>> On 27 Apr 2014, at 13:05, Simon Iten <itensi...@gmail.com> wrote: >>>>>> >>>>>>> crosspost! sorry about the noise. thanks for the inputs i will try to >>>>>>> to this. not sure if i can. otherwise i will ask back if that’s ok! >>>>>>> On 27 Apr 2014, at 13:03, Simon Iten <itensi...@gmail.com> wrote: >>>>>>> >>>>>>>> so if i would measure at the peak of the sawtooth and would upsample >>>>>>>> inside the pd patch, i would get higher resolution, right? >>>>>>>> >>>>>>>> any ideas how i can measure at the peak? (using the rpole output on >>>>>>>> both samphold inputs does not work and delaying one of them is also >>>>>>>> not working) >>>>>>>> >>>>>>>> which >>>>>>>> >>>>>>>> i would highly recommend you try this method with your gk-3 equipped >>>>>>>> guitar (one for each string) since you only have to cover a two octave >>>>>>>> range per string the error is tolerable. (you can add an offset to >>>>>>>> make it fit) >>>>>>>> On 27 Apr 2014, at 12:56, Miller Puckette <m...@ucsd.edu> wrote: >>>>>>>> >>>>>>>>> That is an excellent, witty way to measure pulse withs using >>>>>>>>> only tilde obects - my hat's off to you. >>>>>>>>> >>>>>>>>> The methond only has limited accuracy since its measurement is in >>>>>>>>> samples. For instance, a 1/2 cycle of a 440-hz. tone at 44.1 kHz is >>>>>>>>> only 50 samples, so there's only 2% accuracy. That's about 1/3 of a >>>>>>>>> half tone (30-ish cents) which would sound horribly out of tune. >>>>>>>>> >>>>>>>>> There's an alternative sine-to-sawtooth recipe described here: >>>>>>>>> >>>>>>>>> http://msp.ucsd.edu/Publications/icmc10.pdf >>>>>>>>> >>>>>>>>> This is the basis of my guitar processing patch, smeck, but should be >>>>>>>>> more >>>>>>>>> broadly useful. But it has its own limitations: the sawtooth you get >>>>>>>>> out >>>>>>>>> is wiggly if the input sn't a pure sinusoid. >>>>>>>>> >>>>>>>>> There's also the possibility of simply pitch tracking with sigmund~. >>>>>>>>> Use >>>>>>>>> a maximum frequency around 6000 and a maximum of 6 partals (default >>>>>>>>> 50!) >>>>>>>>> for best results. >>>>>>>>> >>>>>>>>> cheers >>>>>>>>> M >>>>>>>>> >>>>>>>>> On Sun, Apr 27, 2014 at 11:27:33AM +0200, Simon Iten wrote: >>>>>>>>>> dear list, >>>>>>>>>> >>>>>>>>>> i have a strange problem with my “sinetosawtooth” patch. >>>>>>>>>> >>>>>>>>>> it is basically a version of the pitch to voltage conversion used in >>>>>>>>>> the old gr300 guitar synths from roland. >>>>>>>>>> >>>>>>>>>> i cut out all the clutter to make it easier to look at and >>>>>>>>>> understand. (cut out the adaptive filtering at the input since i use >>>>>>>>>> a sine wave for this example and not a guitar string) >>>>>>>>>> >>>>>>>>>> here is how it works (or should): >>>>>>>>>> >>>>>>>>>> -an input signal gets amplified by a large factor and clipped. this >>>>>>>>>> squares the input. >>>>>>>>>> >>>>>>>>>> -the square wave is converted to pulses. >>>>>>>>>> >>>>>>>>>> -the pulses from the rising of the square wave are used to set and >>>>>>>>>> reset an accumulating filter (rpole~) >>>>>>>>>> >>>>>>>>>> this results in a sawtooth wave that varies in amplitude depending >>>>>>>>>> on the frequency of the input. >>>>>>>>>> >>>>>>>>>> -a sample and hold samples the peak of the sawtooth and holds it >>>>>>>>>> until the next peak occurs. this, after a conversion gives us the >>>>>>>>>> input frequency. yeah! >>>>>>>>>> >>>>>>>>>> in the example patch i used the falling edges of the square >>>>>>>>>> wave to trigger the sample and hold. this samples the sawtooth >>>>>>>>>> amplitude after half the rising. (this is also why i have 22050 in >>>>>>>>>> fexpr~ and not 44100) i could not figure out how to sample the peak >>>>>>>>>> of the sawtooth, so suggestions here are very welcome. >>>>>>>>>> >>>>>>>>>> now to the problem: >>>>>>>>>> >>>>>>>>>> the extracted frequency does not exactly correspond to the input >>>>>>>>>> frequency. it is pretty close at low frequencies but gets worse at >>>>>>>>>> higher frequencies. the factor is not constant. at even higher >>>>>>>>>> frequencies (around 5000 hertz) the reported frequency gets totally >>>>>>>>>> out of control. >>>>>>>>>> >>>>>>>>>> i first thought this is because the samphold~ object is inaccurate. >>>>>>>>>> but i then saw that the sawtooth wave from the rpole~ object has no >>>>>>>>>> constant amplitude even with the input frequency not changing. so it >>>>>>>>>> seems that either rpole~ or change~ is not accurate. >>>>>>>>>> >>>>>>>>>> or the problem is that i sample in the middle of the rising and not >>>>>>>>>> at the top ( as described earlier) >>>>>>>>>> >>>>>>>>>> attached the sinetosawtooth patch. set your sound card to 44100 or >>>>>>>>>> change the 22050 in fexpr~ to half the sampling frequency. >>>>>>>>>> >>>>>>>>>> i would really appreciate if somebody could have a look at this, >>>>>>>>>> >>>>>>>>>> thanks, simon >>>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> Pd-list@iem.at mailing list >>>>>>>>>> UNSUBSCRIBE and account-management -> >>>>>>>>>> http://lists.puredata.info/listinfo/pd-list >>>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>> >> >
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