function [num, den, tim] = rcosiir(r, T_delay, rate, T, tol, fil_type, col)
%RCOSIIR Design a raised cosine IIR filter.
%
%   WARNING: RCOSIIR has been removed.
%
%   [NUM, DEN] = RCOSIIR(R, T_DELAY, RATE, T, TOL) designs an IIR 
%   approximation of the equivalent FIR raised cosine filter with a
%   specified rolloff factor R. T_DELAY specifies the delay which must be
%   an integer multiple of T.  RATE is the number of sample points in each
%   interval T, or the sampling rate of the filter is T/RATE. The default
%   value of RATE is 5. T is the symbol interval. The order of the IIR
%   filter is determined by TOL when it is an integer greater than 1. If
%   TOL is less than 1, it is considered as the relative tolerance in the
%   SVD computation in selecting the order. The default value of TOL is
%   0.01. The time response of the raised cosine filter has the form of
%
%     h(t) = sinc(t/T) cos(pi R t/T)/(1 - 4 R^2 t^2 /T^2)
%
%   The frequency domain has the spectrum
%
%             / T                                 when 0 < |f| < (1-r)/2/T
%             |         pi T         1-R    T           1-R         1+R
%     H(f) = < (1 + cos(----) (|f| - ----) ---    when  --- < |f| < ---
%             |           r           2T    2           2 T         2 T
%             \ 0                                 when |f| > (1+r)/2/T
%
%   [NUM, DEN] = RCOSIIR(R, T_DELAY, RATE, T, TOL, FILTER_TYPE) designs an
%   IIR approximation of the equivalent FIR square root raised cosine
%   filter if FILTER_TYPE == 'sqrt'.
%
%   RCOSIIR(...) plots the time response and frequency response of the
%   raised cosine filter
%
%   RCOSIIR(..., COL) plots the time response and frequency response using
%   the color specified in the string variable COL. The string in COL can
%   be any type as defined in PLOT.
%
%   [NUM, DEN, SAMPLE_TIME] = RCOSIIR(...) returns the IIR filter and the
%   sample time for the filter.
%
%   See also RCOSDESIGN, RCOSDEMO.

%   Copyright 1996-2023 The MathWorks, Inc.

error(message('comm:rcosiir:willBeRemovedNoRep', 'rcosiir'));
