LMS also simulink

Hi All, 

I am wanting to implement LMS algo in simulink without using the LMS block
given in simulink library.

 My problem is that ,I want to apply the calculated filter coefficients to
the ''input'' of the LMS block constantly to make it similar to the
''desired'' . But the problem is e.g. if the ''input'' and ''desired''
becomes same the filter coeffients recduces to a filter with  unit impulse
response.
In general i am wanting to calculate the filter coefficients that can make
''input'' similar as ''desired'' by applying some filter coefficients on
''input'' but as the ''input'' is approaching ''desired'' the filter
coefficients should not turn towards unity rather keeps the value of the
coefficients because of which the 'input' has reached 'desired'

i would be glad if someone can help me in finding out the simulink model
of LMS algo.

Thanks a lot for your helps- 

On Tue, 15 Jan 2008 06:54:58 -0600, "me_chilled" <a.azizz@gmail.com>
wrote:

>Hi All, 
>
>I am wanting to implement LMS algo in simulink without using the LMS block
>given in simulink library.
>
> My problem is that ,I want to apply the calculated filter coefficients to
>the ''input'' of the LMS block constantly to make it similar to the
>''desired'' . But the problem is e.g. if the ''input'' and ''desired''
>becomes same the filter coeffients recduces to a filter with  unit impulse
>response.
>In general i am wanting to calculate the filter coefficients that can make
>''input'' similar as ''desired'' by applying some filter coefficients on
>''input'' but as the ''input'' is approaching ''desired'' the filter
>coefficients should not turn towards unity rather keeps the value of the
>coefficients because of which the 'input' has reached 'desired'

I think you're missing one important detail: in equalization the
needed functionality is to make the output of the adaptive equalizer
(your LMS) to be the same as the desired not input. Generally you have
no control over the input (it goes through some media which has
frequency dependent attenuation and fading). The equalizer is a filter
which process its input to produce the output and you want output to
be what you want ie desired signal. In general when output is |e|
similar to desired output, your filter coefficients are said to have
converged and may look like the unit pulse at some delay only if the
input needed no equalization but this is an exception.