srrc_trans_filter.m

此代码仿真了一个语音输入输出系统

% SRRC_TRANS_FILTER    Applies a square root raised cosine filter to the
%   BPSK signal as it leaves the transmitter.
%   This square root raised cosine filter is the first of two
%   in cascade.  Because the MATLAB rcosflt function does not 
%   allow Fs (the filter's sampling frequency) and Fd (the 
%   input's sampling frequency) to be equal, this filter's output
%   will be an upsampled version of the input.

%   Completeed: July 24, 2005

%   Terrence Irving
%   2005 NSF REU in SDR
%   Stevens Institute of Technology
%   Hoboken, NJ USA



% Globalize object handles that this component must access.
global srrc_1_pb sssa_base done_text_fontsize srrc_trans_done_dims bpsk_pb

% Globalize the appropriate data created by this component.
global trans_carrier_filtered

% Change previous button's color (MATLAB 7 precaution).
set(bpsk_pb, 'backgroundcolor', 'white');
set(bpsk_pb, 'foregroundcolor', 'black');

% Set up filter parameters.
Fd = 1;                     % input signal's sampling rate
Fs = 2;                     % filter's sampling rate

% Create and apply a square root raised cosine filter.
disp('Filtering transmission carrier signal');
trans_carrier_filtered = rcosflt(carrier, Fd, Fs, 'sqrt');
disp('Transmission carrier signal filtered');
disp(' '); % blank line

% Free memory.
clear Fd Fs;

% Change button color and update text when component is finished.
set(srrc_1_pb, 'backgroundcolor', 'white');
set(srrc_1_pb, 'foregroundcolor', 'black');
srrc_1_done = uicontrol(sssa_base,...
    'style', 'text',...
    'fontsize', done_text_fontsize,...
    'foregroundcolor', 'white',...
    'backgroundcolor', [.5 0 0],... % matches background image color
    'horizontalalignment', 'center',...
    'string', 'DONE',...
    'position', srrc_trans_done_dims); 

% Pause for one second before continuing, giving the button time to update.
pause(1); 

% Continue on.
srrc_rec_filter;