puthex.m

FS1016源代码

% MATLAB SIMULATION OF NSA FS-1016 CELP v3.2
% COPYRIGHT (C) 1995-99 ANDREAS SPANIAS AND TED PAINTER
%
% This Copyright applies only to this particular MATLAB implementation
% of the FS-1016 CELP coder.  The MATLAB software is intended only for educational
% purposes.  No other use is intended or authorized.  This is not a public
% domain program and distribution to individuals or networks is strictly
% prohibited.  Be aware that use of the standard in any form is goverened
% by rules of the US DoD.  Therefore patents and royalties may apply to
% authors, companies, or committees associated with this standard, FS-1016.  For
% questions regarding the MATLAB implementation please contact Andreas
% Spanias at [phone].  For questions on rules,
% royalties, or patents associated with the standard, please contact the DoD.
%
% ALL DERIVATIVE WORKS MUST INCLUDE THIS COPYRIGHT NOTICE.
%
% ******************************************************************
% PUTHEX
%
% PORTED TO MATLAB FROM CELP 3.2a C RELEASE
% 7-28-94
%
% ******************************************************************
%
% DESCRIPTION
%
% Convert binary bit stream input to hex bit stream output
%
% DESIGN NOTES
%
% Pack an array of binary bits into a string of hex characters,
% where each character represents 4 bits.  The character stream is
% nb/4 characters long.
%
% VARIABLES
%
% INPUTS
%   nb         -     Number of bits in the input bit stream
%   bits       -     Bit stream input data (binary)
%
% OUTPUTS
%   line       -     Bit stream output data (hex)
%
% INTERNALS
%   WordStart  -     Indicies of high-order bits for each hex word
%   w          -     Current 4-bit word (1 to nb/4)
%
% ******************************************************************

function line = puthex( nb, bits )

% INIT HEX WORD BASE INDICIES
WordStart = 1:4:nb;

% PACK 4-BIT BINARY WORDS INTO HEX DIGITS
% NOTE THE USE OF LEADING 0 TO FORCE UNSIGNED CONVERSIONS
for w = 1:fix(nb/4)
    line(w) = sprintf( '%X', bin2int( [0,bits(WordStart(w):WordStart(w)+3)'] ) );
end