单路DDS与多路DDS_多相dds信号合成

不考虑频率分辨率、量化噪声，仅为验证之用

clc;clear all;close all;

%-- 生成DDS_ROM
N = 16384;
sin_rom = zeros(1,N);
cos_rom = zeros(1,N);
for m=0:N-1
    sin_rom(1,m+1) = sin(m/N*2*pi);
    cos_rom(1,m+1) = sin(m/N*2*pi);
end

%-- 单路DDS输出
FS = 5000;
f  = 1000;
freq_word  = round(f/FS*N);
phase_word = 0;
phase      = 0;
single_dds_sig = zeros(1,N);
for m=0:N-1
    if m== 0
        phase = freq_word + phase_word;
    else
        phase = freq_word + phase;
    end
    phase_addr = mod(phase,N);
    if phase_addr == 0
        phase_addr = 1;
    end
    single_dds_sig(1,m+1) = sin_rom(1,phase_addr);
end
y = abs(fft(single_dds_sig));
figure;
plot(20*log10(y/max(y)));
title('单路DDS输出');

%-- 多路DDS输出
FS  = 5000;
f   = 1000;
NUM = 16;
freq_word  = NUM*round(f/FS*N);
phase_word = linspace(0,NUM-1,NUM)*round(f/FS*N);
phase      = -linspace(1,NUM,NUM)*round(f/FS*N);

multi_dds_sig = zeros(NUM,N/NUM);
for m=1:NUM
    for k=0:N/NUM-1
        if k==0
            phase(1,m) = freq_word + phase_word(1,m);
        else
            phase(1,m) = freq_word + phase(1,m);
        end
        phase_addr = mod(phase(1,m),N);
        if phase_addr == 0
            phase_addr = 1;
        end
        multi_dds_sig(m,k+1) = sin_rom(1,phase_addr);
    end
end
multi_dds_sig_new = reshape(multi_dds_sig,1,N);
y = abs(fft(multi_dds_sig_new));
figure;
plot(20*log10(y/max(y)));
title('多路DDS输出');

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