Subject: Re: [AUDITORY] seeking old Kaiser paper From: Robert Zatorre <robert.zatorre@xxxxxxxx> Date: Mon, 19 Feb 2018 09:32:09 -0500 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>--------------CE20CAB68C44C0588878C50E Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: quoted-printable As a moral to this story, may I humbly suggest what I tell my=20 undergraduates: that if a Google Search does not turn up much, you might=20 actually need to do a bit more investigation before drawing conclusions.=20 Scholarly work can begin with Google, of course, but it should certainly=20 not end there. Robert Zatorre, PhD Montreal Neurological Institute McGill University 3801 University St Montreal, QC Canada H3A2B4 www.zlab.mcgill.ca On 19-Feb-18 2:20 AM, Richard F. Lyon wrote: > I asked Leland Jackson; he says "Yes, Roberts et al did great work at=20 > Colorado, but were initially better known in the controls community.=C2= =A0=20 > I knew Dick Roberts best and was greatly saddened when he died at a=20 > young age." > Looks like he died in 1990, according to his 1992 book: > https://books.google.com/books?id=3DhSDvAAAAMAAJ&q=3D%22richard+a+rober= ts%22&dq=3D%22richard+a+roberts%22&hl=3Den&sa=3DX&ved=3D0ahUKEwigpZD-r7HZ= AhWGx4MKHU7sD8wQ6AEIOTAD=20 > <https://books.google.com/books?id=3DhSDvAAAAMAAJ&q=3D%22richard+a+robe= rts%22&dq=3D%22richard+a+roberts%22&hl=3Den&sa=3DX&ved=3D0ahUKEwigpZD-r7H= ZAhWGx4MKHU7sD8wQ6AEIOTAD> > > His "book on Signal Detectability in 1965" was his dissertation at=20 > University of Michigan. > > And Robert A. Gabel went from Colorado to MIT Lincoln Laboratory,=20 > where he was for 25 years by 2009, says here: > http://news.mit.edu/2009/qcc-0527 > > Dick > > > On Thu, Feb 15, 2018 at 8:06 AM, Richard F. Lyon <dicklyon@xxxxxxxx=20 > <mailto:dicklyon@xxxxxxxx>> wrote: > > It seems unlikely that a couple of guys from Denver and Boulder, > who wrote three editions of a good book, and authored some other > papers, would not be legit. > > Here are papers by Richard A. Roberts: > https://scholar.google.com/scholar?hl=3Den&as_sdt=3D1%2C5&q=3D%22RI= CHARD+A.+ROBERTS%22 > <https://scholar.google.com/scholar?hl=3Den&as_sdt=3D1%2C5&q=3D%22R= ICHARD+A.+ROBERTS%22> > > He wrote a book on Signal Detectability in 1965: > https://books.google.com/books?id=3DHUtXFud4u_8C&q=3Dinauthor:%22Ri= chard+A.+Roberts%22&dq=3Dinauthor:%22Richard+A.+Roberts%22&hl=3Den&sa=3DX= &ved=3D0ahUKEwj_v8fspajZAhUP-J8KHft6CdMQ6AEIPTAE > <https://books.google.com/books?id=3DHUtXFud4u_8C&q=3Dinauthor:%22R= ichard+A.+Roberts%22&dq=3Dinauthor:%22Richard+A.+Roberts%22&hl=3Den&sa=3D= X&ved=3D0ahUKEwj_v8fspajZAhUP-J8KHft6CdMQ6AEIPTAE> > (so he probably retired before the web became a big thing). > > and he wrote a book on DSP in 1987: > https://books.google.com/books?id=3DGiBoQgAACAAJ&dq=3D%22richard+a+= roberts%22&hl=3Den&sa=3DX&ved=3D0ahUKEwj7q5i5pajZAhUEwlQKHeqBAeUQ6AEIKTAA > <https://books.google.com/books?id=3DGiBoQgAACAAJ&dq=3D%22richard+a= +roberts%22&hl=3Den&sa=3DX&ved=3D0ahUKEwj7q5i5pajZAhUEwlQKHeqBAeUQ6AEIKTA= A> > and a book on probability in 1992: > https://books.google.com/books?id=3DhSDvAAAAMAAJ&q=3Dinauthor:%22Ri= chard+A.+Roberts%22&dq=3Dinauthor:%22Richard+A.+Roberts%22&hl=3Den&sa=3DX= &ved=3D0ahUKEwj_v8fspajZAhUP-J8KHft6CdMQ6AEINDAC > <https://books.google.com/books?id=3DhSDvAAAAMAAJ&q=3Dinauthor:%22R= ichard+A.+Roberts%22&dq=3Dinauthor:%22Richard+A.+Roberts%22&hl=3Den&sa=3D= X&ved=3D0ahUKEwj_v8fspajZAhUP-J8KHft6CdMQ6AEINDAC> > > Robert A. Gabel was with Bede Liu at Princeton, and then C.U. > Boulder EE department according to this paper: > https://www.osapublishing.org/ao/abstract.cfm?uri=3Dao-9-5-1180 > <https://www.osapublishing.org/ao/abstract.cfm?uri=3Dao-9-5-1180> > and looks like maybe he became or physiologist, or is that someone > with the same name? > https://scholar.google.com/scholar?hl=3Den&as_sdt=3D1%2C5&q=3D%22ro= bert+a+gabel%22&btnG=3D > <https://scholar.google.com/scholar?hl=3Den&as_sdt=3D1%2C5&q=3D%22r= obert+a+gabel%22&btnG=3D> > > Dick > > > > On Thu, Feb 15, 2018 at 7:25 AM, Sharath chandra > <looplogic@xxxxxxxx <mailto:looplogic@xxxxxxxx>> wrote: > > Dear Richard > > I've heard of this thing going around called 'predatory > publishing'. It's has dark underground roots, involving > amazing manuscripts and books that capture the essence of > leading research from different sources compiled into a single > publication, written by a team of 'ghost authors' > > There is a high chance that Gabel and Roberts are fictitious > names/ghost authorships of what indeed could be a book of > amazing content. > Google search for these authors reveals close to nothing. > > Regards > Sharath > > > > > On Tuesday, February 13, 2018, Richard F. Lyon > <dicklyon@xxxxxxxx <mailto:dicklyon@xxxxxxxx>> wrote: > > More on gammatones in the Gabel & Roberts "Signals and > Linear Systems" book: > > I got the 1980 second edition and 1973 first edition.=C2=A0 > Like the 1987 third, they have a table of z transforms of > sampled impulse responses of gammatone-like filters > (complex gammatones); the second and third go to order 4, > but the first goes all the way to order 5!=C2=A0 The fifth > order has numerator [1, 11, 11, 1], which I haven't > checked, but seems plausible; that makes zeros at z =3D > -9.8990, -1.0000, -0.1010. > > In terms of the funny correction to impulse invariance for > impulses with a step at t =3D 0 that Leland Jackson and > Wolfgang Mecklenbra=C3=BCker separately published in 2000, = yes, > it's in all three editions of Gabel & Roberts, going back > to 1973; and not quite in any of Jim Kaiser's papers. > > Speaking of Jim Kaiser, I sent him a copy of my book, > which was delivered yesterday; his son says "He couldn't > remember receiving the book yesterday. Our healthcare > worker found the book this morning on his night stand.=C2=A0= He > had already started reading it but forgot that he had!=C2=A0= He > appreciated your inscription.=C2=A0 He was able to recall y= our > interactions at Bell in the early 70's.=C2=A0 Long term mem= ory > still seems relatively good."=C2=A0 Jim is 89, living in Ch= apel > Hill NC. > > One other reader of this list tells me he's a big fan of > Gabel & Roberts, recently read it cover to cover, and is > planning to use it for a course.=C2=A0 It's still in print = at a > low price in Asian markets. > > I repeat my question: does anybody know these guys (Robert > A. Gabel and/or Richard A. Roberts)? > > Dick > > > > > > On Thu, Feb 1, 2018 at 7:19 PM, Richard F. Lyon > <dicklyon@xxxxxxxx <mailto:dicklyon@xxxxxxxx>> wrote: > > I got a copy that Jim Beauchamp found in a library > near him.=C2=A0 Thanks, Jim. > > If anyone wants a copy, let me know.=C2=A0 Or of the 19= 64 > Golden & Kaiser BSTJ paper. > > The "correction" term in the 1966 version is not there > in 1963, nor in 1964. > > The correction term would not be needed, and the > problem would never have existed, if the discrete > impulse response at h[0] had been defined in terms of > the continuous impulse response h(t) as (h(0-) + > h(0+)/2; that is, as the average across the step > discontinuity at 0 if there is one, as two different > papers in 2000 pointed out. The examples in the older > papers and the correction term in the 1966 paper make > it clear that such a reasonable choice was not made at > that time. > > This issue (but not its history) is covered in great > detail in the 1987 book Signals and Linear Systems, > third edition, by Gabel and Roberts (does anyone know > these guys?).=C2=A0 I haven't looked at earlier edition= s. > They not only discuss the discontinuity in depth, but > also address repeated poles, which are ignored in most > treatments, and provide a table up to order 4 repeated > poles, which agrees precisely with Volker Hohmann's > derivation of zeros in the numerator of the > impulse-invariance design of discrete-time complex > gammatone filters: a numerator [1, 4, 1] independent > of pole frequencies and dampings, yielding zeros at z > =3D -3.7321 and z =3D -0.2679, which do just a little > smoothing on top of the repeated-poles filter. > > Dick > > > On Mon, Jan 29, 2018 at 8:15 PM, Richard F. Lyon > <dicklyon@xxxxxxxx <mailto:dicklyon@xxxxxxxx>> wrote: > > Does anyone have the 1963 Proceedings of the First > Allerton Conference on Circuit and System Theory?=C2= =A0 > Or just "Design methods for sampled-data filters" > by J. F. Kaiser? > > I'm trying to resolve a disconnect in derivations > of the impulse-invariance method, which was > "corrected" in several places over the years, > though Kaiser had the key to the correction in his > chapter "Digital Filters" in the 1966 "System > Analysis by Digital Computer" book, in which he > says his stuff on IIR design closely follows that > missing paper as well as a BSTJ paper that does > not have the key piece. > > The key observation is that using the naive > impulse invariance method adds a constant > (frequency independent) term to the frequency > response of the digital filter proportional to the > impulse response on the right side of time zero: > T/2 * h(0+). He didn't go as far as the > "corrections" which said to take the impulse > response h[k] at k =3D 0 to be (h(0-) + h(0+))/2, > though it's pretty obvious from there. It's funny > that at some point he got as far as including that > unwanted term yet didn't comment on the easy way > to remove it. Maybe in the missing paper... > > Dick > > > > > > --------------CE20CAB68C44C0588878C50E Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable <html> <head> <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Dutf= -8"> </head> <body text=3D"#000000" bgcolor=3D"#FFFFFF"> As a moral to this story, may I humbly suggest what I tell my undergraduates: that if a Google Search does not turn up much, you might actually need to do a bit more investigation before drawing conclusions. Scholarly work can begin with Google, of course, but it should certainly not end there.<br> <pre class=3D"moz-signature" cols=3D"72">Robert Zatorre, PhD Montreal Neurological Institute McGill University 3801 University St Montreal, QC Canada H3A2B4 <a class=3D"moz-txt-link-abbreviated" href=3D"http://www.zlab.mcgill.ca">= www.zlab.mcgill.ca</a></pre> <div class=3D"moz-cite-prefix">On 19-Feb-18 2:20 AM, Richard F. Lyon wrote:<br> </div> <blockquote type=3D"cite" cite=3D"mid:31055_1519026908_5A8A82DC_31055_331_1_CAA=3DYKqjzdx0w1hECzNHH= OFLN=3D70W2wS5s8aZ8TAOJuoZH0-rCg@xxxxxxxx"> <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Du= tf-8"> <div dir=3D"ltr"> <div> <div>I asked Leland Jackson; he says "Yes, Roberts et al did great work at Colorado, but were initially better known in the controls community.=C2=A0 I knew Dick Roberts best and wa= s greatly saddened when he died at a young age."<br> </div> Looks like he died in 1990, according to his 1992 book:<br> <a href=3D"https://books.google.com/books?id=3DhSDvAAAAMAAJ&q=3D%22richa= rd+a+roberts%22&dq=3D%22richard+a+roberts%22&hl=3Den&sa=3DX&a= mp;ved=3D0ahUKEwigpZD-r7HZAhWGx4MKHU7sD8wQ6AEIOTAD" target=3D"_blank" moz-do-not-send=3D"true">https://books.goog= le.com/<wbr>books?id=3DhSDvAAAAMAAJ&q=3D%<wbr>22richard+a+roberts%22&= amp;dq=3D%<wbr>22richard+a+roberts%22&hl=3Den&<wbr>sa=3DX&ved= =3D0ahUKEwigpZD-<wbr>r7HZAhWGx4MKHU7sD8wQ6AEIOTAD</a><br> <br> </div> <div>His "book on Signal Detectability in 1965" was his dissertation at University of Michigan.<br> </div> <div><br> </div> <div>And Robert A. Gabel went from Colorado to MIT Lincoln Laboratory, where he was for 25 years by 2009, says here:<br> <a href=3D"http://news.mit.edu/2009/qcc-0527" moz-do-not-send=3D"true">http://news.mit.edu/2009/qcc-0527</a= ><br> </div> <div><br> </div> Dick<br> <div><br> <div class=3D"gmail_extra"><br> <div class=3D"gmail_quote">On Thu, Feb 15, 2018 at 8:06 AM, Richard F. Lyon <span dir=3D"ltr"><<a href=3D"mailto:dicklyon@xxxxxxxx" target=3D"_blank" moz-do-not-send=3D"true">dicklyon@xxxxxxxx</a>></span= > wrote:<br> <blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0= px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><span> <div dir=3D"ltr"> <div>It seems unlikely that a couple of guys from Denver and Boulder, who wrote three editions of a good book, and authored some other papers, would not be legit.<br> <br> </div> <div>Here are papers by Richard A. Roberts:<br> <a href=3D"https://scholar.google.com/scholar?hl=3Den&as_sdt=3D1%2C5&= ;q=3D%22RICHARD+A.+ROBERTS%22" target=3D"_blank" moz-do-not-send=3D"true">https:= //scholar.google.com/sch<wbr>olar?hl=3Den&as_sdt=3D1%2C5&q=3D%22R= <wbr>ICHARD+A.+ROBERTS%22</a><br> </div> <div><br> He wrote a book on Signal Detectability in 1965:<br= > <a href=3D"https://books.google.com/books?id=3DHUtXFud4u_8C&q=3Dinauthor= :%22Richard+A.+Roberts%22&dq=3Dinauthor:%22Richard+A.+Roberts%22&= hl=3Den&sa=3DX&ved=3D0ahUKEwj_v8fspajZAhUP-J8KHft6CdMQ6AEIPTAE" target=3D"_blank" moz-do-not-send=3D"true">https:= //books.google.com/books<wbr>?id=3DHUtXFud4u_8C&q=3Dinauthor:%<wbr>22= Richard+A.+Roberts%22&dq=3D<wbr>inauthor:%22Richard+A.+<wbr>Roberts%2= 2&hl=3Den&sa=3DX&ved=3D<wbr>0ahUKEwj_v8fspajZAhUP-J8KHft6C<wb= r>dMQ6AEIPTAE</a><br> </div> <div>(so he probably retired before the web became a big thing).<br> <br> </div> <div>and he wrote a book on DSP in 1987:<br> <a href=3D"https://books.google.com/books?id=3DGiBoQgAACAAJ&dq=3D%22rich= ard+a+roberts%22&hl=3Den&sa=3DX&ved=3D0ahUKEwj7q5i5pajZAhUEwl= QKHeqBAeUQ6AEIKTAA" target=3D"_blank" moz-do-not-send=3D"true">https:= //books.google.com/books<wbr>?id=3DGiBoQgAACAAJ&dq=3D%22richard<wbr>+= a+roberts%22&hl=3Den&sa=3DX&ved=3D0<wbr>ahUKEwj7q5i5pajZAhUEw= lQKHeqBAe<wbr>UQ6AEIKTAA</a><br> </div> <div>and a book on probability in 1992:<br> <a href=3D"https://books.google.com/books?id=3DhSDvAAAAMAAJ&q=3Dinauthor= :%22Richard+A.+Roberts%22&dq=3Dinauthor:%22Richard+A.+Roberts%22&= hl=3Den&sa=3DX&ved=3D0ahUKEwj_v8fspajZAhUP-J8KHft6CdMQ6AEINDAC" target=3D"_blank" moz-do-not-send=3D"true">https:= //books.google.com/books<wbr>?id=3DhSDvAAAAMAAJ&q=3Dinauthor:%<wbr>22= Richard+A.+Roberts%22&dq=3D<wbr>inauthor:%22Richard+A.+<wbr>Roberts%2= 2&hl=3Den&sa=3DX&ved=3D<wbr>0ahUKEwj_v8fspajZAhUP-J8KHft6C<wb= r>dMQ6AEINDAC</a><br> <br> </div> <div>Robert A. Gabel was with Bede Liu at Princeton, and then C.U. Boulder EE department according to this paper:<br> <a href=3D"https://www.osapublishing.org/ao/abstract= .cfm?uri=3Dao-9-5-1180" target=3D"_blank" moz-do-not-send=3D"true">https:= //www.osapublishing.org/<wbr>ao/abstract.cfm?uri=3Dao-9-5-118<wbr>0</a><b= r> </div> <div>and looks like maybe he became or physiologist, or is that someone with the same name?<br> </div> <div><a href=3D"https://scholar.google.com/scholar?hl=3Den&as_sdt=3D1%2C5&= ;q=3D%22robert+a+gabel%22&btnG=3D" target=3D"_blank" moz-do-not-send=3D"true">https:= //scholar.google.com/sch<wbr>olar?hl=3Den&as_sdt=3D1%2C5&q=3D%22r= <wbr>obert+a+gabel%22&btnG=3D</a><br> <br> </div> Dick<br> <br> <br> </div> </span> <div class=3D"gmail_extra"><br> <div class=3D"gmail_quote"><span>On Thu, Feb 15, 2018 a= t 7:25 AM, Sharath chandra <span dir=3D"ltr"><<a href=3D"mailto:looplogic@xxxxxxxx" target=3D"_blank" moz-do-not-send=3D"true">loop= logic@xxxxxxxx</a>></span> wrote:<br> </span> <div> <div class=3D"gmail-m_5389312762144718194h5"> <blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> <div dir=3D"ltr">Dear Richard <div><br> </div> <div>I've heard of this thing going around called 'predatory publishing'. It's has dark underground roots, involving amazing manuscripts and books that capture the essence of leading research from different sources compiled into a single publication, written by a team of 'ghost authors'</div> <div><br> </div> <div>There is a high chance that Gabel and Roberts are fictitious names/ghost authorships of what indeed could be a book of amazing content.=C2=A0</div> <div>Google search for these authors reveals close to nothing.</div> <div><br> </div> <div>Regards<span class=3D"gmail-m_5389312762144718194m_533= 4541293323984831HOEnZb"><font color=3D"#888888"><br> Sharath</font></span></div> <div><br> </div> <div><br> </div> <div><span><br> <br> On Tuesday, February 13, 2018, Richard F. Lyon <<a href=3D"mailto:dicklyon@xxxxxxxx" target=3D"_blank" moz-do-not-send=3D"tr= ue">dicklyon@xxxxxxxx</a>> wrote:<br> </span> <blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> <div dir=3D"ltr"><span> <div> <div> <div> <div>More on gammatones in the Gabel & Roberts "Signals and Linear Systems" book:<br> <br> </div> I got the 1980 second edition and 1973 first edition.=C2=A0 L= ike the 1987 third, they have a table of z transforms of sampled impulse responses of gammatone-like filters (complex gammatones); the second and third go to order 4, but the first goes all the way to order 5!=C2=A0 The fifth order has numerator [1, 11, 11, 1], which I haven't checked, but seems plausible; that makes zeros at z =3D -9.8990, -1.0000, -0.1010.<br> <br> </div> In terms of the funny correction to impulse invariance for impulses with a step at t =3D 0 that Leland Jackson and Wolfgang Mecklenbra=C3=BCker separately published in 2000, yes, it's in all three editions of Gabel & Roberts, going back to 1973; and not quite in any of Jim Kaiser's papers.<br> <br> Speaking of Jim Kaiser, I sent him a copy of my book, which was delivered yesterday; his son says "He couldn't remember receiving the book yesterday.=C2=A0 Our healthcare worker found the book this morning on his night stand.=C2=A0 He had already start= ed reading it but forgot that he had!=C2=A0 He appreciated your inscription.=C2=A0 He was able to recall your interactions at Bell in the early 70's.=C2=A0 Long ter= m memory still seems relatively good."=C2=A0 Jim is 89, living in Chapel Hill NC.<br> <br> </div> One other reader of this list tells me he's a big fan of Gabel & Roberts, recently read it cover to cover, and is planning to use it for a course.=C2=A0 It's sti= ll in print at a low price in Asian markets.<br> <br> </div> <div>I repeat my question: does anybody know these guys (Robert A. Gabel and/or Richard A. Roberts)?<b= r> </div> <div><br> </div> Dick<br> <br> </span> <div> <div class=3D"gmail-m_538931276214471819= 4m_5334541293323984831h5"> <div><br> <div><br> <br> </div> <div class=3D"gmail_extra"><br> <div class=3D"gmail_quote">On Thu, Feb 1, 2018 at 7:19 PM, Richard F. Lyon <span dir=3D"ltr"><<a href=3D"mailto:dicklyon@xxxxxxxx= cm.org" target=3D"_blank" moz-do-not-send=3D"true">= dicklyon@xxxxxxxx</a>></span> wrote:<br> <blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-le= ft:1ex"> <div dir=3D"ltr"><span> <div> <div> <div> <div>I got a copy that Jim Beauchamp found in a library near him.=C2=A0 Than= ks, Jim.<br> <br> </div> If anyone wants a copy, let me know.=C2=A0 Or of= the 1964 Golden & Kaiser BSTJ paper.<br> <br> </div> The "correction" term in the 1966 version is not there in 1963, nor in 1964.<br> <br> </div> The correction term would not be needed, and the problem would never have existed, if the discrete impulse response at h[0] had been defined in terms of the continuous impulse response h(t) as (h(0-) + h(0+)/2; that is, as the average across the step discontinuity at 0 if there is one, as two different papers in 2000 pointed out.=C2=A0 The examples in the older papers and the correction term in the 1966 paper make it clear that such a reasonable choice was not made at that time.</div> <div><br> </div> <div>This issue (but not its history) is covered in great detail in the 1987 book Signals and Linear Systems, third edition, by Gabel and Roberts (does anyone know these guys?).=C2=A0 I haven't looked at earlier editions.=C2=A0 They not only discuss the discontinuity in depth, but also address repeated poles, which are ignored in most treatments, and provide a table up to order 4 repeated poles, which agrees precisely with Volker Hohmann's derivation of zeros in the numerator of the impulse-invariance design of discrete-time complex gammatone filters: a numerator [1, 4, 1] independent of pole frequencies and dampings, yielding zeros at z =3D -3.732= 1 and z =3D -0.2679, which do just a little smoothing on top of the repeated-poles filter.<br> </div> <div><br> </div> Dick<br> <br> </span> <div class=3D"gmail_extra= "><br> <div class=3D"gmail_quote"= ><span>On Mon, Jan 29, 2018 at 8:15 PM, Richard F. Lyon <sp= an dir=3D"ltr"><<= a href=3D"mailto:dicklyon@xxxxxxxx" target=3D"_blank" moz-do-not-send=3D"tru= e">dicklyon@xxxxxxxx</a>></span> wrote:<br> </span> <div> <div> <blockquote class=3D"gmail_= quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204= );padding-left:1ex"> <div> <div> <div dir=3D"ltr= "> <div> <div> <div>Does anyone have the 1963 Proceedings of the First Allerton Conference on Circuit and System Theory?=C2=A0 O= r just "Design methods for sampled-data filters" by J. F. Kaiser?=C2=A0= <br> <br> </div> I'm trying to resolve a disconnect in derivations of the impulse-invaria= nce method, which was "corrected" in several places over the years, though Kaiser had the key to the correction in his chapter "Digital Filters" in the 1966 "System Analysis by Digital Computer" book, in which he says his stuff on IIR design closely follows that missing paper as well as a BSTJ paper that does not have the key piece.=C2=A0 <b= r> <br> </div> The key observation is that using the naive impulse invariance method adds a constant (frequency independent) term to the frequency response of the digital filter proportional to the impulse response on the right side of time zero: T/2 * h(0+).=C2= =A0 He didn't go as far as the "corrections" which said to take the impulse response h[k] at k =3D 0 to b= e (h(0-) + h(0+))/2, though it's pretty obvious from there.=C2=A0 It's funny that at some point he got as far as including that unwanted term yet didn't comment on the easy way to remove it.=C2=A0 Maybe in the missing paper...<br> <br> </div> Dick<br> <br> <div> <div><br> </div> </div> </div> </div> </div> </blockquote> </div> </div> </div> <br> </div> </div> </blockquote> </div> <br> </div> </div> </div> </div> </div> </blockquote> </div> </div> </blockquote> </div> </div> </div> <br> </div> </blockquote> </div> <br> </div> </div> </div> </blockquote> <br> </body> </html> --------------CE20CAB68C44C0588878C50E--