fun_gb_qam.m

DTTB（中国数字地面电视标准）数字电视均衡仿真分析

function output_modu = fun_GB_QAM(input_frame, index)

% ----- 函数功能说明： 国标QAM调制程序 ----- %

% index:  modulation index
%		2---4qam    %%（国标）
%		4---16qam   %%（国标）
%		6---64qam   %%（国标）
% 	   else is error

f_length = length(input_frame)/index;
QAM_input_I = zeros(1,f_length);
QAM_input_Q = zeros(1,f_length);

switch index
case 2,
    QAM_4_IQ = [-4.5 4.5];   
    QAM_input_I = QAM_4_IQ(input_frame(2:2:end)+1);
    QAM_input_Q = QAM_4_IQ(input_frame(1:2:end)+1);
    output_modu = QAM_input_I + j * QAM_input_Q;
case 4,
    QAM_16_IQ = [-6 -2 6 2];   
    QAM_input_I = QAM_16_IQ(input_frame(3:4:end)*2+input_frame(4:4:end)+1);
    QAM_input_Q = QAM_16_IQ(input_frame(1:4:end)*2+input_frame(2:4:end)+1);
    output_modu = QAM_input_I + j * QAM_input_Q;
case 6,
    QAM_64_IQ = [-7 -5 -1 -3 7 5 1 3];  
    QAM_input_I = QAM_64_IQ(input_frame(4:6:end)*4+input_frame(5:6:end)*2+input_frame(6:6:end)+1);
    QAM_input_Q = QAM_64_IQ(input_frame(1:6:end)*4+input_frame(2:6:end)*2+input_frame(3:6:end)+1);
    output_modu = QAM_input_I + j * QAM_input_Q;
end