Reply by Mukul Bhatnagar ●July 17, 20022002-07-17
Its fun trying to implement LMS on Matlab, but if you
are pressed for time, there should be couple of
examples on the web , for instance
http://www.utdallas.edu/~golden/MATHANN/ANNSOFTWARE.html

or can try
http://wwwpub.utdallas.edu/~emd/adaptshort.html
Thanks
-Mukul
--- Jeff Brower <> wrote:
> Premkiran Mannava-
>
> Thanks for your inquiry. I don't think I can help
> with this. Please reply to the
> group.
>
> Jeff Brower
> DSP sw/hw engineer
> Signalogic
>
> -------- Original Message --------
> Subject: Re: [matlab] Re: problem in normalization
> factor in low pass filter
> implementation
> Date: Wed, 17 Jul 2002 12:13:53 +0100 (BST)
> From: premkiran mannava
> <>
> To: Jeff Brower < >
> Hello sir,
>
> Could you help me out with a matlab program which is
> written for widro hoff lms
> algorithm for adaptive filtering? It is needed as a
> part for my work and it is
> urgent. if possible write the code itself
>
> kiran >
> Jeff Brower <> wrote:
>
> Henry-
>
> You're not reading carefully. I said all of the
> "x[n]" components, like
> this:
>
> y(n) = 2*y(n-1) - y(n-2) + x(n)/8 - x(n-3)/4 +
> x(n-6)/8
>
> Jeff Brower
> DSP sw/hw engineer
> Signalogic > i_am_henry wrote:
> >
> > Hi Jeff,
> >
> > Thank you for you help first.
> >
> > Yes, I have applied the gain/normalization
> factor (1/8) to all the
> > input components according to the equation.
> >
> > However, for
> > y(n) = 2*y(n-1) - y(n-2) + x(n) - 2*x(n-3) +
> x(n-6)
> > the filter response tranfer function is
> > Yn 1 - 2*z^-3 + z^-6
> > ---- = -------------------- ..............
> (1)
> > Xn 1 - 2*z^-1 + z^-2
> >
> >
> > For
> > y(n) = 1/8 * (2*y(n-1) - y(n-2) + x(n) -
> 2*x(n-3) + x(n-6))
> > the filter response tranfer function is
> > Yn 1 - 2*z^-3 + z^-6
> > ---- = -------------------- ..............
> (2)
> > Xn 8 - 2*z^-1 + z^-2
> >
> > The filter frequency respose of Equ. (2) is
> different from (1).
> >
> > Regards
> > Henry Chang
> > Assistant Computer Officer
> > Chinese Univerisity of HK
> >
> > --- In matlab@y..., Jeff Brower wrote:
> > > Henry-
> > >
> > > Are you sure the gain factor (1/8) is not
> supposed to be applied to
> > the x[n]
> > > components only? What happens if you try
> that?
> > >
> > > Typically the gain/normalization factor is
> intended to insure unity
> > gain (or desired
> > > gain) in the passband, but the frequency
> response of the filter
> > (shape) should remain
> > > unchanged.
> > >
> > > Jeff Brower
> > > DSP sw/hw engineer
> > > Signalogic
> > >
> > >
> > > i_am_henry wrote:
> > > >
> > > > Dear all,
> > > >
> > > > Currently, I am working on implementing
> recursive low pass
> > filter
> > > > with design equation extracted from
> manual
> > > > y(n) = 2*y(n-1) - y(n-2) + x(n) -
> 2*x(n-3) + x(n-6)
> > > >
> > > > The frequency response of the filter is
> good.
> > > >
> > > > However, the manual also mention, in
> actual implementation,
> > there
> > > > is a normalization factor of 1/8 based
> upon the gain of the
> > filter.
> > > > That is, the equation become:
> > > > y(n) = 1/8 * (2*y(n-1) - y(n-2) + x(n) -
> 2*x(n-3) + x(n-6))
> > > >
> > > > But the frequency response of this filter
> is bad.
> > > >
> > > > Is it some common practice to design a
> filter with desired good
> > > > frequency response but later add some
> normalization factor to
> > > > normalize the signal? What is the
> advantage to do so?
> > > >
> > > > Thank you for your help.
> > > >
> > > > Henry

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