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function [ START ] = make_start(Lh,SYMBOLS)
%
% MAKE_START:
% This code returns a statenumber corresponding to the start
% state as it is found from Lh. The method is to use the table
% of symbolic start states as it is listed in the report made
% by 95gr870T. For the table lookups are made in SYMBOLS. in
% order to map from the symbol representation to the state number
% representation.
%
% SYNTAX: [ START ] = make_start(Lh,SYMBOLS)
%
% INPUT: SYMBOLS: The table of symbols corresponding the the state-
% numbers.
% Lh: Length of the estimated impulseresponse.
%
% OUTPUT: START: The number representation of the legal start state.
%
% SUB_FUNC: None
%
% WARNINGS: The table of symbolic representations has not been verified
% but is used directly as it is listed in the report made
% by 95gr870T.
%
% TEST(S): The function has been verified to return a state number
% which matches the symbolic representation.
%
% AUTOR: Jan H. Mikkelsen / Arne Norre Ekstrøm
% EMAIL: hmi@kom.auc.dk / aneks@kom.auc.dk
%
% $Id: make_start.m,v 1.2 1997/09/22 11:40:17 aneks Exp $
% WE HAVEN'T FOUND IT YET.
%
START_NOT_FOUND = 1;
% OBTAIN THE SYMBOLS FROM Lh. THIS IS THE TABLE LISTED IN THE REPORT MADE
% BY 95gr870T. (SATEREPRESENTATION IS SLIGHTLY CHANGED).
%
if Lh==1,
start_symbols = [ 1 ];
elseif Lh==2,
start_symbols = [ 1 -j ];
elseif Lh==3,
start_symbols = [ 1 -j -1 ];
elseif Lh==4,
start_symbols = [ 1 -j -1 j ];
elseif Lh==5,
start_symbols = [ 1 -j -1 j 1];
else
fprintf('\n\nError: Illegal value of Lh, terminating...');
end
% NOW MAP FROM THE SYMBOLS TO A STATE NUMBER BY SEARCHING
% SYMBOLS.
%
START=0;
while START_NOT_FOUND,
START=START+1;
if sum(SYMBOLS(START,:)==start_symbols)==Lh,
START_NOT_FOUND=0;
end
end
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