low_pass.m

这个程序主要是实现空时编码的matlab编解码仿真。

function [lp_data_block]=low_pass(cutoff_freq, order, data_block)

%   [lp_data_block]=low_pass(cutoff_freq, order, data_block)
%
%	Output:
%	lp_data_block   - The lowpass-filtered version of data_block
%	
%   Input:
%   cutoff_freq     - Desired cutoff frequency for the filter
%   order           - Butterworth filter of this order is used when filtering
%   data_block      - The input data_block to be filtered
%
%   Short Theoretical Background for the Function:
%
%   Low-pass filters the input datablock. This function is
%   probably called from the function down_converter.
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
%%% Function part of simulation for Space-Time
%%% coding project, group Grey-2001.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%   Author: Stefan Uppg錼d
%   Date: 2001-03-20
%   Version: 1.0
%   Revision (Name & Date):
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

[B,A]=butter(order, cutoff_freq);           % cutoff_freq have to be chosen to eliminate
                                            % high-frequency parts after down-conversion.
lp_data_block = filter(B,A,data_block);