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# remez

Remez exchange algorithm for the weighted chebyshev approximation of a continuous function with a sum of cosines.

### Syntax

an=remez(guess,mag,fgrid,weight)

### Arguments

- guess
real array of size

`n+2 the`

initial guess- fgrid
real array of size

`ng`

: the grid of normalized frequency points in [0,.5[- mag
real array of size

`ng`

: the desired magnitude on grid`fg`

- weight
real array of size

`ng`

: weighting function on error on grid`fg`

- an
real array of size

`n`

: cosine coefficients

### Description

Minimax approximation of a frequency domain magnitude response. The approximation takes the form

An FIR, linear-phase filter can be obtained from the output of
`remez`

by using the following commands:

hn(1:nc-1)=an(nc:-1:2)/2; hn(nc)=an(1); hn(nc+1:2*nc-1)=an(2:nc)/2;

This function is mainly intended to be called by the remezb function.

### Bibliography

E.W. Cheney, Introduction to Approximation Theory, McGraw-Hill, 1966

### References

This function is based on the fortran code `remez.f`

written by:

James H. Mcclellan, department of electrical engineering and computer science, Massachusetts Institute of Technology, Cambridge, Massachussets. 02139

Thomas W. Parks, department of electrical engineering, Rice university, Houston, Texas 77001

Thomas W. Parks, department of electrical engineering, Rice university, Houston, Texas 77001

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