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Hello!

I have read article "Optimum Masking Levels and Coefficient Sparseness for
Hilbert Transformers and Half-Band Filters Designed Using the
Frequency-Response Masking Technique", Yong Ching Lim, NOVEMBER 2005.

There're in example two filters Hb(z) and H1(z). I guess they derived by
multiplication classical hilbert impulse function h(n)=[1-cos(Pi*n)]/Pi*n
on different windows. What kind of windows is using there?
Thanks for any help.

Best regards,
Vasily

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On 18 Mar, 14:09, "Junglist" <vasily.karpenko@n_o_s_p_a_m.gmail.com>
wrote:
> Hello!
>
> I have read article "Optimum Masking Levels and Coefficient Sparseness for
> Hilbert Transformers and Half-Band Filters Designed Using the
> Frequency-Response Masking Technique", Yong Ching Lim, NOVEMBER 2005.
>
> There're in example two filters Hb(z) and H1(z). I guess they derived by
> multiplication classical hilbert impulse function h(n)=[1-cos(Pi*n)]/Pi*n
> on different windows. What kind of windows is using there?
> Thanks for any help.

I don't have access to that particular IEEE journal, but
browsing some of the author's other articles that I do
have access to, it seems one key paper to look for
is reference [1],

Y. C. Lim,  "Frequency-response masking approach for the
synthesis of sharp linear phase digital filter",  IEEE Trans.
Circuits Syst.,  vol. CAS-33,  no. 4,  pp. 1986 .

Don't be surprised if you find the answer in that article.

Rune

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On Mar 18, 6:09=A0am, "Junglist" <vasily.karpenko@n_o_s_p_a_m.gmail.com>
wrote:
> Hello!
>
> I have read article "Optimum Masking Levels and Coefficient Sparseness fo=
r
> Hilbert Transformers and Half-Band Filters Designed Using the
> Frequency-Response Masking Technique", Yong Ching Lim, NOVEMBER 2005.
>
> There're in example two filters Hb(z) and H1(z). I guess they derived by
> multiplication classical hilbert impulse function h(n)=3D[1-cos(Pi*n)]/Pi=
*n
> on different windows. What kind of windows is using there?
> Thanks for any help.
>
> Best regards,
> Vasily

Why do you suggest the use of windows here? The frequency response
masking literature takes advantage of a variety of filter design
methods, but usually optimizing techniques.

The original reference is:
Optimum masking levels and coefficient sparseness for Hilbert
transformers and half-band filters designed using the frequency-
response masking technique
Yong Ching Lim ; Ya Jun Yu ; Saramaki, T. ;
Sch. of Electr. & Electron. Eng., Nanyang Technol. Univ., Singapore
Circuits and Systems I: Regular Papers, IEEE Transactions on
Nov. 2005, Vol. 52 , Issue:11, page(s): 2444 - 2453

and the correct info for Rune's reference is:
Y. C. Lim,  "Frequency-response masking approach for the synthesis of
sharp linear phase digital filter",  IEEE Trans. Circuits Syst.,  vol.
CAS-33,  no. 4,  pp. 357, 1986
(it was incomplete on the IEEE site)

Dale B. Dalrymple

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>I don't have access to that particular IEEE journal, but
>browsing some of the author's other articles that I do
>have access to, it seems one key paper to look for
>is reference [1],

>Rune
>

If you're interesting link to this article:
http://dr.ntu.edu.sg/bitstream/handle/10220/6006/coefficient%20sparseness%20for%20Hilbert%20transformers%20and%20half-ba
nd%20filters%20designed%20using%20the%20frequency-response%20masking%20technique.pdf?sequence=1

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On Mar 18, 9:09=A0am, "Junglist" <vasily.karpenko@n_o_s_p_a_m.gmail.com>
wrote:
> Hello!
>
> I have read article "Optimum Masking Levels and Coefficient Sparseness fo=
r
> Hilbert Transformers and Half-Band Filters Designed Using the
> Frequency-Response Masking Technique", Yong Ching Lim, NOVEMBER 2005.
>
> There're in example two filters Hb(z) and H1(z). I guess they derived by
> multiplication classical hilbert impulse function h(n)=3D[1-cos(Pi*n)]/Pi=
*n
> on different windows. What kind of windows is using there?
> Thanks for any help.
>
> Best regards,
> Vasily

Perhaps this paper will shed some light for you:

http://www.ece.umassd.edu/Faculty/acosta/ICASSP/ICASSP_1996/pdf/ic961272.pd=
f

IHTH,
Clay

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On Mar 18, 11:52=A0am, dbd <d...@ieee.org> wrote:
> On Mar 18, 6:09=A0am, "Junglist" <vasily.karpenko@n_o_s_p_a_m.gmail.com>
> wrote:
>
> > Hello!
>
> > I have read article "Optimum Masking Levels and Coefficient Sparseness =
for
> > Hilbert Transformers and Half-Band Filters Designed Using the
> > Frequency-Response Masking Technique", Yong Ching Lim, NOVEMBER 2005.
>
> > There're in example two filters Hb(z) and H1(z). I guess they derived b=
y
> > multiplication classical hilbert impulse function h(n)=3D[1-cos(Pi*n)]/=
Pi*n
> > on different windows. What kind of windows is using there?
..
> Why do you suggest the use of windows here? The frequency response
> masking literature takes advantage of a variety of filter design
> methods, but usually optimizing techniques.

an implied window can come from any design technique as long as you
can avoid dividing a non-zero numerator by a zero denominator.

because half-band symmetry let's us ditch the even-numbered taps, any
design that imposes half-band symmetry can have its (properly aligned)
impulse response divided by the ideal

   h[n] =3D (1 - (-1)^n)/(pi*n)        (h[0]=3D0)

for odd n, and you have an implied window.

r b-j

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On Mar 18, 6:23=A0pm, robert bristow-johnson <r...@audioimagination.com>
wrote:
> On Mar 18, 11:52=A0am, dbd <d...@ieee.org> wrote:
>
>
>
>
>
> > On Mar 18, 6:09=A0am, "Junglist" <vasily.karpenko@n_o_s_p_a_m.gmail.com=
>
> > wrote:
>
> > > Hello!
>
> > > I have read article "Optimum Masking Levels and Coefficient Sparsenes=
s for
> > > Hilbert Transformers and Half-Band Filters Designed Using the
> > > Frequency-Response Masking Technique", Yong Ching Lim, NOVEMBER 2005.
>
> > > There're in example two filters Hb(z) and H1(z). I guess they derived=
 by
> > > multiplication classical hilbert impulse function h(n)=3D[1-cos(Pi*n)=
]/Pi*n
> > > on different windows. What kind of windows is using there?
> ..
> > Why do you suggest the use of windows here? The frequency response
> > masking literature takes advantage of a variety of filter design
> > methods, but usually optimizing techniques.
>
> an implied window can come from any design technique as long as you
> can avoid dividing a non-zero numerator by a zero denominator.
>
> because half-band symmetry let's us ditch the even-numbered taps, any
> design that imposes half-band symmetry can have its (properly aligned)
> impulse response divided by the ideal
>
> =A0 =A0h[n] =3D (1 - (-1)^n)/(pi*n) =A0 =A0 =A0 =A0(h[0]=3D0)
>
> for odd n, and you have an implied window.
>
> r b-j- Hide quoted text -
>
> - Show quoted text -

True, but the article refers to Chebyshev approximation and the effect
the masking has on its ripple, so I assume he's using a Remez method
to obtain his original filters. And then "sharpening" them from there.

My 2 cents worth anyway.

Clay

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On Mar 19, 10:29=A0am, Clay <c...@claysturner.com> wrote:
> On Mar 18, 6:23=A0pm, robert bristow-johnson <r...@audioimagination.com>
> wrote:
>
>
>
> > On Mar 18, 11:52=A0am, dbd <d...@ieee.org> wrote:
>
> > > On Mar 18, 6:09=A0am, "Junglist" <vasily.karpenko@n_o_s_p_a_m.gmail.c=
om>
> > > wrote:
>
> > > > Hello!
>
> > > > I have read article "Optimum Masking Levels and Coefficient Sparsen=
ess for
> > > > Hilbert Transformers and Half-Band Filters Designed Using the
> > > > Frequency-Response Masking Technique", Yong Ching Lim, NOVEMBER 200=
5.
>
> > > > There're in example two filters Hb(z) and H1(z). I guess they deriv=
ed by
> > > > multiplication classical hilbert impulse function h(n)=3D[1-cos(Pi*=
n)]/Pi*n
> > > > on different windows. What kind of windows is using there?
> > ..
> > > Why do you suggest the use of windows here? The frequency response
> > > masking literature takes advantage of a variety of filter design
> > > methods, but usually optimizing techniques.
>
> > an implied window can come from any design technique as long as you
> > can avoid dividing a non-zero numerator by a zero denominator.
>
> > because half-band symmetry let's us ditch the even-numbered taps, any
> > design that imposes half-band symmetry can have its (properly aligned)
> > impulse response divided by the ideal
>
> > =A0 =A0h[n] =3D (1 - (-1)^n)/(pi*n) =A0 =A0 =A0 =A0(h[0]=3D0)
>
> > for odd n, and you have an implied window.
>
...
>
> True, but the article refers to Chebyshev approximation and the effect
> the masking has on its ripple, so I assume he's using a Remez method
> to obtain his original filters. And then "sharpening" them from there.

still, an implied window can be derived from the data as long as there
are no 1/0 kind of division.  even when using Parks-McClellan, you can
enforce half-band symmetry, which will make the even samples zero.
then the conditions are met and an implied window can be observed.

r b-j

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On Mar 20, 5:06=A0pm, robert bristow-johnson <r...@audioimagination.com>
wrote:
> On Mar 19, 10:29=A0am, Clay <c...@claysturner.com> wrote:
>
>
>
>
>
> > On Mar 18, 6:23=A0pm, robert bristow-johnson <r...@audioimagination.com=
>
> > wrote:
>
> > > On Mar 18, 11:52=A0am, dbd <d...@ieee.org> wrote:
>
> > > > On Mar 18, 6:09=A0am, "Junglist" <vasily.karpenko@n_o_s_p_a_m.gmail=
.com>
> > > > wrote:
>
> > > > > Hello!
>
> > > > > I have read article "Optimum Masking Levels and Coefficient Spars=
eness for
> > > > > Hilbert Transformers and Half-Band Filters Designed Using the
> > > > > Frequency-Response Masking Technique", Yong Ching Lim, NOVEMBER 2=
005.
>
> > > > > There're in example two filters Hb(z) and H1(z). I guess they der=
ived by
> > > > > multiplication classical hilbert impulse function h(n)=3D[1-cos(P=
i*n)]/Pi*n
> > > > > on different windows. What kind of windows is using there?
> > > ..
> > > > Why do you suggest the use of windows here? The frequency response
> > > > masking literature takes advantage of a variety of filter design
> > > > methods, but usually optimizing techniques.
>
> > > an implied window can come from any design technique as long as you
> > > can avoid dividing a non-zero numerator by a zero denominator.
>
> > > because half-band symmetry let's us ditch the even-numbered taps, any
> > > design that imposes half-band symmetry can have its (properly aligned=
)
> > > impulse response divided by the ideal
>
> > > =A0 =A0h[n] =3D (1 - (-1)^n)/(pi*n) =A0 =A0 =A0 =A0(h[0]=3D0)
>
> > > for odd n, and you have an implied window.
>
> ...
>
> > True, but the article refers to Chebyshev approximation and the effect
> > the masking has on its ripple, so I assume he's using a Remez method
> > to obtain his original filters. And then "sharpening" them from there.
>
> still, an implied window can be derived from the data as long as there
> are no 1/0 kind of division. =A0even when using Parks-McClellan, you can
> enforce half-band symmetry, which will make the even samples zero.
> then the conditions are met and an implied window can be observed.
>
> r b-j- Hide quoted text -
>
> - Show quoted text -

I wasn't saying you can't do it this way, but rather I was reflecting
on the OP's question about what window or how the particular filters
in the article were created.

Clay

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