Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
Hi Alexandre, This is the online tool: http://kmt.hku.nl/~pieter/cgi-bin/resp/nph-PZT.cgi. It starts with an example and every time you refresh the page it gives you a new one. If you scroll down there's a link that tells you how the coefficients were calculated, e.g.: 2 zeros give 3 coefficients: *a0* = G *a1* = -G(Z0 + Z1) *a2* = G(Z0*Z1) 2 poles give 3 coefficients: *b0* = 1 *b1* = -(P0 + P1) *b2* = (P0*P1) The linear difference equation is derived from these as you can see. Regards, --Funs On Tue, Sep 24, 2013 at 7:36 AM, Alexandre Torres Porres por...@gmail.comwrote: for what i see, it's not some sort of straight formula, right? seems a bit more complicated than that. cheers 2013/9/23 Funs Seelen funssee...@gmail.com On Mon, Sep 23, 2013 at 5:35 PM, Alexandre Torres Porres por...@gmail.com wrote: thanks, here's a pic of what I have so far https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/11212_10151872996046683_1825736206_n.jpg Cool. For extra inspiration you could have a look at PoZeTools It sure does look like what I need. Thanks. But extracting what I need to know about the math of converting from coordinates to coefficients was just over my head :P unfortunately, sorry. I was hoping for something simpler, like just the operations needed. If the info is in code, I need it to more explicit. I'd really appreciate if anyone knows how to read from this and just points it out for me so I can put it in a patch. I'm assuming it's rather simple math I remember I once learned how to do this but never repeated the practice. If I find time to do that I would gladly try to figure it out again, but if someone more experienced feels the urge to chime in before that time I would be very happy too :). ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
Hey Alexandre, This blog - EarLevel Engineeringhttp://www.earlevel.com/main/2003/02/28/biquads/ - really helped with my understanding of poles/zeros and biquads. Hope it's useful! Cheers, Joe On 24 September 2013 06:36, Alexandre Torres Porres por...@gmail.comwrote: for what i see, it's not some sort of straight formula, right? seems a bit more complicated than that. cheers 2013/9/23 Funs Seelen funssee...@gmail.com On Mon, Sep 23, 2013 at 5:35 PM, Alexandre Torres Porres por...@gmail.com wrote: thanks, here's a pic of what I have so far https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/11212_10151872996046683_1825736206_n.jpg Cool. For extra inspiration you could have a look at PoZeTools It sure does look like what I need. Thanks. But extracting what I need to know about the math of converting from coordinates to coefficients was just over my head :P unfortunately, sorry. I was hoping for something simpler, like just the operations needed. If the info is in code, I need it to more explicit. I'd really appreciate if anyone knows how to read from this and just points it out for me so I can put it in a patch. I'm assuming it's rather simple math I remember I once learned how to do this but never repeated the practice. If I find time to do that I would gladly try to figure it out again, but if someone more experienced feels the urge to chime in before that time I would be very happy too :). ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list -- Follow me on Twitter @diplojocus ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
This is the online tool: http://kmt.hku.nl/~pieter/cgi-bin/resp/nph-PZT.cgi. damn, it says it cant load it here :P but this seems like a simple formula to try out, from what you copied here. If that's all, and if I got what it means, I can see a patch coming right now :) let's see! thanks 2013/9/24 Funs Seelen funssee...@gmail.com Hi Alexandre, This is the online tool: http://kmt.hku.nl/~pieter/cgi-bin/resp/nph-PZT.cgi. It starts with an example and every time you refresh the page it gives you a new one. If you scroll down there's a link that tells you how the coefficients were calculated, e.g.: 2 zeros give 3 coefficients: *a0* = G *a1* = -G(Z0 + Z1) *a2* = G(Z0*Z1) 2 poles give 3 coefficients: *b0* = 1 *b1* = -(P0 + P1) *b2* = (P0*P1) The linear difference equation is derived from these as you can see. Regards, --Funs On Tue, Sep 24, 2013 at 7:36 AM, Alexandre Torres Porres por...@gmail.com wrote: for what i see, it's not some sort of straight formula, right? seems a bit more complicated than that. cheers 2013/9/23 Funs Seelen funssee...@gmail.com On Mon, Sep 23, 2013 at 5:35 PM, Alexandre Torres Porres por...@gmail.com wrote: thanks, here's a pic of what I have so far https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/11212_10151872996046683_1825736206_n.jpg Cool. For extra inspiration you could have a look at PoZeTools It sure does look like what I need. Thanks. But extracting what I need to know about the math of converting from coordinates to coefficients was just over my head :P unfortunately, sorry. I was hoping for something simpler, like just the operations needed. If the info is in code, I need it to more explicit. I'd really appreciate if anyone knows how to read from this and just points it out for me so I can put it in a patch. I'm assuming it's rather simple math I remember I once learned how to do this but never repeated the practice. If I find time to do that I would gladly try to figure it out again, but if someone more experienced feels the urge to chime in before that time I would be very happy too :). ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
one doubt emerges really soon anyway. Since they are complex (there are two coordinate numbers for each pole and zero) how do I get only one number by, for example, summing or multiplying one pole to the other? as in: *b1* = -(P0 + P1) *b2* = (P0*P1) cheers! 2013/9/24 Alexandre Torres Porres por...@gmail.com This is the online tool: http://kmt.hku.nl/~pieter/cgi-bin/resp/nph-PZT.cgi. damn, it says it cant load it here :P but this seems like a simple formula to try out, from what you copied here. If that's all, and if I got what it means, I can see a patch coming right now :) let's see! thanks 2013/9/24 Funs Seelen funssee...@gmail.com Hi Alexandre, This is the online tool: http://kmt.hku.nl/~pieter/cgi-bin/resp/nph-PZT.cgi. It starts with an example and every time you refresh the page it gives you a new one. If you scroll down there's a link that tells you how the coefficients were calculated, e.g.: 2 zeros give 3 coefficients: *a0* = G *a1* = -G(Z0 + Z1) *a2* = G(Z0*Z1) 2 poles give 3 coefficients: *b0* = 1 *b1* = -(P0 + P1) *b2* = (P0*P1) The linear difference equation is derived from these as you can see. Regards, --Funs On Tue, Sep 24, 2013 at 7:36 AM, Alexandre Torres Porres por...@gmail.com wrote: for what i see, it's not some sort of straight formula, right? seems a bit more complicated than that. cheers 2013/9/23 Funs Seelen funssee...@gmail.com On Mon, Sep 23, 2013 at 5:35 PM, Alexandre Torres Porres por...@gmail.com wrote: thanks, here's a pic of what I have so far https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/11212_10151872996046683_1825736206_n.jpg Cool. For extra inspiration you could have a look at PoZeTools It sure does look like what I need. Thanks. But extracting what I need to know about the math of converting from coordinates to coefficients was just over my head :P unfortunately, sorry. I was hoping for something simpler, like just the operations needed. If the info is in code, I need it to more explicit. I'd really appreciate if anyone knows how to read from this and just points it out for me so I can put it in a patch. I'm assuming it's rather simple math I remember I once learned how to do this but never repeated the practice. If I find time to do that I would gladly try to figure it out again, but if someone more experienced feels the urge to chime in before that time I would be very happy too :). ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
hey joe, this blog is awesome, I stumbled upon it too, they even have an applet that does the job I want, but no code or formulas around :P it's the closest thing I found on the subject in the internet... weird how I can't seem to find these formulas on google and all... cheers 2013/9/24 Joe White white.j...@gmail.com Hey Alexandre, This blog - EarLevel Engineeringhttp://www.earlevel.com/main/2003/02/28/biquads/ - really helped with my understanding of poles/zeros and biquads. Hope it's useful! Cheers, Joe On 24 September 2013 06:36, Alexandre Torres Porres por...@gmail.comwrote: for what i see, it's not some sort of straight formula, right? seems a bit more complicated than that. cheers 2013/9/23 Funs Seelen funssee...@gmail.com On Mon, Sep 23, 2013 at 5:35 PM, Alexandre Torres Porres por...@gmail.com wrote: thanks, here's a pic of what I have so far https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/11212_10151872996046683_1825736206_n.jpg Cool. For extra inspiration you could have a look at PoZeTools It sure does look like what I need. Thanks. But extracting what I need to know about the math of converting from coordinates to coefficients was just over my head :P unfortunately, sorry. I was hoping for something simpler, like just the operations needed. If the info is in code, I need it to more explicit. I'd really appreciate if anyone knows how to read from this and just points it out for me so I can put it in a patch. I'm assuming it's rather simple math I remember I once learned how to do this but never repeated the practice. If I find time to do that I would gladly try to figure it out again, but if someone more experienced feels the urge to chime in before that time I would be very happy too :). ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list -- Follow me on Twitter @diplojocus ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
On Tue, Sep 24, 2013 at 2:36 PM, Alexandre Torres Porres por...@gmail.comwrote: This is the online tool: http://kmt.hku.nl/~pieter/cgi-bin/resp/nph-PZT.cgi. damn, it says it cant load it here :P It doesn't load here either. Perhaps the server is too busy since I put this link here and sent a thousand robots over. ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
On Tue, Sep 24, 2013 at 2:50 PM, Alexandre Torres Porres por...@gmail.comwrote: one doubt emerges really soon anyway. Since they are complex (there are two coordinate numbers for each pole and zero) how do I get only one number by, for example, summing or multiplying one pole to the other? as in: *b1* = -(P0 + P1) *b2* = (P0*P1) You don't, the coefficients can be complex too. However, I discovered that mirroring (*) every pole and zero results in just real values without imaginary part. I don't have any mathematical proof for this, but it probably wouldn't be too hard to find such. *) adding another pole/zero for each complex one, like z=-j if you already have a z=j. ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
well, not sure what you mean, again way over my head, but I was giving it a hard shot in the dark and it seemed to have worked out :) I just summed both parts of Z0, for instance, and tried the given math, numbers came out! now to make more tests and see if this is consistent, then finish the patch ;) thanks! 2013/9/24 Funs Seelen funssee...@gmail.com On Tue, Sep 24, 2013 at 2:50 PM, Alexandre Torres Porres por...@gmail.com wrote: one doubt emerges really soon anyway. Since they are complex (there are two coordinate numbers for each pole and zero) how do I get only one number by, for example, summing or multiplying one pole to the other? as in: *b1* = -(P0 + P1) *b2* = (P0*P1) You don't, the coefficients can be complex too. However, I discovered that mirroring (*) every pole and zero results in just real values without imaginary part. I don't have any mathematical proof for this, but it probably wouldn't be too hard to find such. *) adding another pole/zero for each complex one, like z=-j if you already have a z=j. ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
On Tue, Sep 24, 2013 at 3:08 PM, Funs Seelen funssee...@gmail.com wrote: On Tue, Sep 24, 2013 at 2:50 PM, Alexandre Torres Porres por...@gmail.com wrote: one doubt emerges really soon anyway. Since they are complex (there are two coordinate numbers for each pole and zero) how do I get only one number by, for example, summing or multiplying one pole to the other? as in: *b1* = -(P0 + P1) *b2* = (P0*P1) You don't, the coefficients can be complex too. However, I discovered that mirroring (*) every pole and zero results in just real values without imaginary part. I don't have any mathematical proof for this, but it probably wouldn't be too hard to find such. I remembered again, it's called the complex conjugate. http://en.wikipedia.org/wiki/Complex_conjugate *) adding another pole/zero for each complex one, like z=-j if you already have a z=j. ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
so you're basically saying all i need to use is use only the real part, right? my frankenstein was working and alive for several times until i tried some bandpass coeff, let's se if i fix this now :) 2013/9/24 Funs Seelen funssee...@gmail.com On Tue, Sep 24, 2013 at 3:08 PM, Funs Seelen funssee...@gmail.com wrote: On Tue, Sep 24, 2013 at 2:50 PM, Alexandre Torres Porres por...@gmail.com wrote: one doubt emerges really soon anyway. Since they are complex (there are two coordinate numbers for each pole and zero) how do I get only one number by, for example, summing or multiplying one pole to the other? as in: *b1* = -(P0 + P1) *b2* = (P0*P1) You don't, the coefficients can be complex too. However, I discovered that mirroring (*) every pole and zero results in just real values without imaginary part. I don't have any mathematical proof for this, but it probably wouldn't be too hard to find such. I remembered again, it's called the complex conjugate. http://en.wikipedia.org/wiki/Complex_conjugate *) adding another pole/zero for each complex one, like z=-j if you already have a z=j. ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
hey, starting to see what you mean much more clear, cool, really excited. Thanks a lot! 2013/9/24 Alexandre Torres Porres por...@gmail.com so you're basically saying all i need to use is use only the real part, right? my frankenstein was working and alive for several times until i tried some bandpass coeff, let's se if i fix this now :) 2013/9/24 Funs Seelen funssee...@gmail.com On Tue, Sep 24, 2013 at 3:08 PM, Funs Seelen funssee...@gmail.comwrote: On Tue, Sep 24, 2013 at 2:50 PM, Alexandre Torres Porres por...@gmail.com wrote: one doubt emerges really soon anyway. Since they are complex (there are two coordinate numbers for each pole and zero) how do I get only one number by, for example, summing or multiplying one pole to the other? as in: *b1* = -(P0 + P1) *b2* = (P0*P1) You don't, the coefficients can be complex too. However, I discovered that mirroring (*) every pole and zero results in just real values without imaginary part. I don't have any mathematical proof for this, but it probably wouldn't be too hard to find such. I remembered again, it's called the complex conjugate. http://en.wikipedia.org/wiki/Complex_conjugate *) adding another pole/zero for each complex one, like z=-j if you already have a z=j. ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
On Tue, Sep 24, 2013 at 3:35 PM, Alexandre Torres Porres por...@gmail.comwrote: so you're basically saying all i need to use is use only the real part, right? No, I meant that I have the idea that the imaginary part in the calculated coefficients will disappear automatically if you add complex conjugates for all poles and zeros, probably when somehow i^2 gets -1 somewhere. But I must say I'm not a mathematician and not sure at all. ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
Checkout [e_beequad] [u_lowpass], [u_highpass1], [u_bandpass], etc in rjlib The [u_lowpass] etc objects calculate the given coefficients for biquad from the desired frequency and bandwidth ... On Sep 24, 2013, at 3:48 AM, pd-list-requ...@iem.at wrote: From: Alexandre Torres Porres por...@gmail.com Subject: Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane) Date: September 24, 2013 12:36:27 AM CDT To: Funs Seelen funssee...@gmail.com Cc: pd-lista puredata pd-list@iem.at for what i see, it's not some sort of straight formula, right? seems a bit more complicated than that. cheers Dan Wilcox @danomatika danomatika.com robotcowboy.com ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
after some shots in the dark, adjustments and stuff, I was able to make it work really well... thanks a lot again, will put this out hopefully soon after I clean it up and include some features. Cheers 2013/9/24 Dan Wilcox danomat...@gmail.com Checkout [e_beequad] [u_lowpass], [u_highpass1], [u_bandpass], etc in rjlib https://github.com/rjdj/rjlib/tree/master/rj The [u_lowpass] etc objects calculate the given coefficients for biquad from the desired frequency and bandwidth ... On Sep 24, 2013, at 3:48 AM, pd-list-requ...@iem.at wrote: *From: *Alexandre Torres Porres por...@gmail.com *Subject: **Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)* *Date: *September 24, 2013 12:36:27 AM CDT *To: *Funs Seelen funssee...@gmail.com *Cc: *pd-lista puredata pd-list@iem.at for what i see, it's not some sort of straight formula, right? seems a bit more complicated than that. cheers Dan Wilcox @danomatika danomatika.com robotcowboy.com ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
On 24/09/13 21:46, Funs Seelen wrote: On Tue, Sep 24, 2013 at 3:35 PM, Alexandre Torres Porres por...@gmail.comwrote: so you're basically saying all i need to use is use only the real part, right? No, I meant that I have the idea that the imaginary part in the calculated coefficients will disappear automatically if you add complex conjugates for all poles and zeros, probably when somehow i^2 gets -1 somewhere. But I must say I'm not a mathematician and not sure at all. indeed it will ... a conjugate is the number with the imaginary part negated ... so adding a number and its conjugate will certainly end up with a real part only. Simon ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
On Tue, Sep 24, 2013 at 6:32 PM, Simon Wise simonzw...@gmail.com wrote: On 24/09/13 21:46, Funs Seelen wrote: On Tue, Sep 24, 2013 at 3:35 PM, Alexandre Torres Porres por...@gmail.comwrote: so you're basically saying all i need to use is use only the real part, right? No, I meant that I have the idea that the imaginary part in the calculated coefficients will disappear automatically if you add complex conjugates for all poles and zeros, probably when somehow i^2 gets -1 somewhere. But I must say I'm not a mathematician and not sure at all. indeed it will ... a conjugate is the number with the imaginary part negated ... so adding a number and its conjugate will certainly end up with a real part only. Yes, true, and the imaginary part disappears as well when multiplying if the real parts are equal, e.g.: i^2 = -1, so ... (0.5 + 0.5i) * (0.5 - 0.5i) = 0.25 + 0.25i - 0.25i - 0.25i^2 = 0.5 Simon __**_ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/** listinfo/pd-list http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
On Tue, Sep 24, 2013 at 6:13 PM, Alexandre Torres Porres por...@gmail.comwrote: after some shots in the dark, adjustments and stuff, I was able to make it work really well... thanks a lot again, will put this out hopefully soon after I clean it up and include some features. Cheers Great! Thank you for the effort of creating this work. I'm looking forward to it :). ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
Hi Alexandre, Great that you're doing this! For extra inspiration you could have a look at PoZeTools (http://kmt.hku.nl/~pieter/SOFT/RESP/html/PoZeTools.html). It's great software by Pieter Suurmond. He's the one who taught me filter design and he probably has some info about Z-transform on his website as well. Regards, --Funs On Mon, Sep 23, 2013 at 7:37 AM, Alexandre Torres Porres por...@gmail.comwrote: Hi there. So, I've been studying a lot about filters, and I'm doing this clone of max's z-plane in Pd. I hope anyone can help me guide where to find how to convert the values of the complex poles and zeros to biquad coefficients. I really needed that... Sorry if I missed it in Miller's book or some other obvious reference, I'm just really a newbie in filter design. Thanks Alex ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
On Mon, Sep 23, 2013 at 5:35 PM, Alexandre Torres Porres por...@gmail.comwrote: thanks, here's a pic of what I have so far https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/11212_10151872996046683_1825736206_n.jpg Cool. For extra inspiration you could have a look at PoZeTools It sure does look like what I need. Thanks. But extracting what I need to know about the math of converting from coordinates to coefficients was just over my head :P unfortunately, sorry. I was hoping for something simpler, like just the operations needed. If the info is in code, I need it to more explicit. I'd really appreciate if anyone knows how to read from this and just points it out for me so I can put it in a patch. I'm assuming it's rather simple math I remember I once learned how to do this but never repeated the practice. If I find time to do that I would gladly try to figure it out again, but if someone more experienced feels the urge to chime in before that time I would be very happy too :). ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
Great that you're doing this! thanks, here's a pic of what I have so far https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/11212_10151872996046683_1825736206_n.jpg For extra inspiration you could have a look at PoZeTools It sure does look like what I need. Thanks. But extracting what I need to know about the math of converting from coordinates to coefficients was just over my head :P unfortunately, sorry. I was hoping for something simpler, like just the operations needed. If the info is in code, I need it to more explicit. I'd really appreciate if anyone knows how to read from this and just points it out for me so I can put it in a patch. I'm assuming it's rather simple math Cheers Alex 2013/9/23 Funs Seelen funssee...@gmail.com Hi Alexandre, Great that you're doing this! For extra inspiration you could have a look at PoZeTools (http://kmt.hku.nl/~pieter/SOFT/RESP/html/PoZeTools.html). It's great software by Pieter Suurmond. He's the one who taught me filter design and he probably has some info about Z-transform on his website as well. Regards, --Funs On Mon, Sep 23, 2013 at 7:37 AM, Alexandre Torres Porres por...@gmail.com wrote: Hi there. So, I've been studying a lot about filters, and I'm doing this clone of max's z-plane in Pd. I hope anyone can help me guide where to find how to convert the values of the complex poles and zeros to biquad coefficients. I really needed that... Sorry if I missed it in Miller's book or some other obvious reference, I'm just really a newbie in filter design. Thanks Alex ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)
for what i see, it's not some sort of straight formula, right? seems a bit more complicated than that. cheers 2013/9/23 Funs Seelen funssee...@gmail.com On Mon, Sep 23, 2013 at 5:35 PM, Alexandre Torres Porres por...@gmail.com wrote: thanks, here's a pic of what I have so far https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/11212_10151872996046683_1825736206_n.jpg Cool. For extra inspiration you could have a look at PoZeTools It sure does look like what I need. Thanks. But extracting what I need to know about the math of converting from coordinates to coefficients was just over my head :P unfortunately, sorry. I was hoping for something simpler, like just the operations needed. If the info is in code, I need it to more explicit. I'd really appreciate if anyone knows how to read from this and just points it out for me so I can put it in a patch. I'm assuming it's rather simple math I remember I once learned how to do this but never repeated the practice. If I find time to do that I would gladly try to figure it out again, but if someone more experienced feels the urge to chime in before that time I would be very happy too :). ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
