>Subject: Adaptive arrays
>From: forevermav2001@yahoo.com  (John)
>Date: 5/7/2004 11:43 PM Eastern Daylight Time
>Message-id: <acad27ed.0405071943.2ca5ac30@posting.google.com>
>
>Hey,
> I need to design an adaptive array for automatic interference
>rejection using the LMS algorithm in MATLAB. There is a target signal
>cos(2*pi*f0*t) and three interference signals cos(2*pi*f0*t) coming in
>at angles of 45, -30 and -60 degrees. The adaptive array will consist
>of eight elements. The input signals are sampled at Ts=2*10^-10 s
>where t=0,Ts,2Ts,3Ts,4Ts...f0=3*10^8 Hz,lambda=1 m and distance
>between neighboring elements d=lambda/2.
> I know how the LMS algorithm works but i don't know how to
>incorporate adaptive arrays with it. After some research I found out
>that interference rejection has something to do with radars. If
>somewone could provide an example code for designing the adaptive
>array it'll be greatly appreciated
>
>
>
I suggest that you look at Chapter 9 of Adaptive Filter Theory by Simon Haykin
(see page 377).

John,

Fourier transform works in the space domain exactly as in 
the time domain.
A three-element coordinate vector x is an analog of time and
a wave number k is an analog of circular frequency \omega.
Once you've written a flat-front wave exp(i*omega*t-i*k*x)
and applied FT to it, working with wave numbers is absolutely
similar to working with frequencies.

The spatial sampling interval d is an analog of the temporal sampling
interval ts, and the condition d <= lambda/2 is the spatial sampling
criterion.

Since k is a vector, all the spatial information is contained in
the direction of k, while its magnitude determines the wavelength or,
which is equivalent, the wave frequency, assuming c is a constant.

I would recommend you the Multidimensional Digital Signal
Processing book by Dudgeon and Mersereau, Chpt 6, for a
start reading, athough someone else may have different
preferences. I like it for its clarity in the subject.

Rgds,
Andrew

P.S. The most interesting situation, when c is a function of
lambda is not discussed in this book, unfortunately.

forevermav2001@yahoo.com (John) wrote in message news:<acad27ed.0405071943.2ca5ac30@posting.google.com>...
> Hey,
>  I need to design an adaptive array for automatic interference
> rejection using the LMS algorithm in MATLAB. There is a target signal
> cos(2*pi*f0*t) and three interference signals cos(2*pi*f0*t) coming in
> at angles of 45, -30 and -60 degrees. The adaptive array will consist
> of eight elements. The input signals are sampled at Ts=2*10^-10 s
> where t=0,Ts,2Ts,3Ts,4Ts...f0=3*10^8 Hz,lambda=1 m and distance
> between neighboring elements d=lambda/2.
>  I know how the LMS algorithm works but i don't know how to
> incorporate adaptive arrays with it. After some research I found out
> that interference rejection has something to do with radars. If
> somewone could provide an example code for designing the adaptive
> array it'll be greatly appreciated

Hey,
 I need to design an adaptive array for automatic interference
rejection using the LMS algorithm in MATLAB. There is a target signal
cos(2*pi*f0*t) and three interference signals cos(2*pi*f0*t) coming in
at angles of 45, -30 and -60 degrees. The adaptive array will consist
of eight elements. The input signals are sampled at Ts=2*10^-10 s
where t=0,Ts,2Ts,3Ts,4Ts...f0=3*10^8 Hz,lambda=1 m and distance
between neighboring elements d=lambda/2.
 I know how the LMS algorithm works but i don't know how to
incorporate adaptive arrays with it. After some research I found out
that interference rejection has something to do with radars. If
somewone could provide an example code for designing the adaptive
array it'll be greatly appreciated