www.pudn.com > LFH_MFSK.rar > LFH_MFSK.m
clc,clear
close all
% 慢跳频系统
% 数据采用 MFSK 调制
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%% 跳频参数设置 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
M = 4; % MFSK
T = 0.001; % 数据比特周期 (s)
L = log2(M);
Ts = L*T; % MFSK 的码符号周期
fm = 50000; % MFSK 信号载频中心频率
fs = 1/Ts; % MFSK 的 M 个单载频的频率间隔 (fs >= 1/Ts)
Bs = M*fs; % MFSK 信号带宽 (跳频频率最小间隔)
Tc = 4*Ts; % 跳频周期 (Tc>=Ts)
K = 32; % 跳频频率个数
fh = 100000; % 跳频信号中心频率
Bt = K*Bs; % 发射信号带宽
t = 0.1; % 仿真时间
fsample = 800000; % 采样速率
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%% 跳频信号产生 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Data_len = floor(t/Ts); % 用户数据长度
Data = randsrc(Data_len,1,(0:M-1)); % 用户数据
%%%%%%%%%%%%%%%% MFSK 调制 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
St_baseband = DMOD(Data,fm, fs, fsample,'fsk', M); % MFSK 信号
% figure, plot(St_baseband),title('MFSK基带信号');
signal_len = length(St_baseband); % 仿真时间内采样数据长度
%%%%%%%%%%%%%%%%%%% 跳频载波产生 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FH_seq = randsrc(ceil(signal_len/fsample/Tc),1,(0:K-1)); % 跳频序列
FH_sin = zeros(signal_len,1); % 本地跳频信号载波
phase = 2*pi*rand;
for i = 1:ceil(signal_len/fsample/Tc)
f2 = fh + (FH_seq(i)*2 - (K-1))*Bs/2; % 跳频频点中心频率
FH_sin((i-1)*fsample*Tc + 1:i*fsample*Tc) = cos(2*pi*f2*(0:fsample*Tc-1)/fsample + phase);
phase = 2*pi*rand; % 随机相位(非相干慢跳频)
% phase = phase + 2*pi*f2*(fsample*Tc)/fsample; % 连续相位(相干慢跳频)
end
FH_sin(signal_len+1:end) = [];
%%%%%%%%%%%%%%%%%%% 跳频信号产生 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
St_mix_fh = FH_sin.*St_baseband; % 跳频调制
N0 = 48; % 宽带带通滤波器阶数
tr_fir_coff = fir1(N0,[2*fh/fsample,2*(fh+2*fm)/fsample]);%[0.25,0.5]); % 发射宽带带通滤波器系数
%%%%%%%%%%%%%%%%%%% 发射信号通过宽带带通滤波器 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
St = zeros(signal_len,1); % 通过宽带滤波器后的发射信号
for i = 1:N0/2
St(i) = tr_fir_coff * [zeros(N0/2-i+1,1);St_mix_fh(1:N0/2+i)];
end
for i = (N0/2+1):(signal_len - N0/2)
St(i) = tr_fir_coff * St_mix_fh(i-N0/2:N0/2+i);
end
for i = (signal_len - N0/2 + 1):signal_len
St(i) = tr_fir_coff * [St_mix_fh(i-N0/2:signal_len);zeros(i+N0/2-signal_len,1)];
end
St = (St-mean(St))/std(St); % 发射信号幅度归一化
figure
subplot(311),plot((0:signal_len-1)/(signal_len)*fsample,abs(fft(St_baseband))),grid on,title([num2str(M),'FSK基带信号频谱']);
subplot(312),plot((0:signal_len-1)/(signal_len)*fsample,abs(fft(St_mix_fh))),grid on,title('跳频混频后信号频谱');
subplot(313),plot((0:signal_len-1)/(signal_len)*fsample,abs(fft(St))),grid on,title('发射信号频谱');
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%% 信道,噪声及干扰设置 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 信道为自由空间传播信道 , 噪声为加性高斯白噪声
SNR = 0; % 加性高斯白噪声信噪比dB
SJR = -5; % 信干比 : 接收信号功率/干扰信号功率
snr = SNR - 10*log10(fsample/2/Bt); % 折算为带内白噪声强度
Jam = zeros(signal_len,1); % 干扰信号
%%%%%%%%%%%%%%%%%%% 干扰信号产生 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Jam_type = 4; % 1:单音干扰
% 2:多音干扰
% 3:噪声调频干扰
% 4:MFSK 干扰
% 其它:仅高斯白噪声干扰
%%% 网控信道干扰率设置 %%%%%%%%%
Jam_percent = 1/2; % 干扰网控信道数比例
% 1/1: 干扰全部网控信道
% 1/2: 干扰1/2网控信道
% 1/3: 干扰1/3网控信道
Jam_ch_num = ceil(K*Jam_percent); % 干扰网控信道数
channel = randperm(K);
channel(Jam_ch_num+1:end) = [];
multi_sin_num = 4; % 多音干扰每信道干扰正弦波数
Jam_M = 4; % MFSK 干扰进制数
switch Jam_type
case 1 %%%%%%%%%%% 单音干扰 %%%%%%%%%%%%%%
f_jam = fh + fm + (channel'-K/2-1/2) * Bs + randsrc(Jam_ch_num,1,(1-M/2:M/2)) * fs - fs/2;
Jam = (cos(2*pi*f_jam*(1:signal_len)/fsample+2*pi*rand))';
Jam = mean(Jam,2);
Jam = (Jam - mean(Jam))/std(Jam);
figure,plot((0:signal_len-1)/(signal_len)*fsample,abs(fft(Jam))),grid on,title('单音干扰信号频谱');
case 2 %%%%%%%%%%% 多音干扰 %%%%%%%%%%%%%%
Jam = zeros(signal_len,multi_sin_num);
for i = 1:Jam_ch_num
f_jam = fh + fm + (channel(i)-K/2) * Bs - rand(multi_sin_num,1) * Bs;
Jam = Jam + (cos(2*pi*f_jam*(1:signal_len)/fsample+2*pi*rand))';
end
Jam = mean(Jam,2);
Jam = (Jam - mean(Jam))/std(Jam);
figure,plot((0:signal_len-1)/(signal_len)*fsample,abs(fft(Jam))),grid on,title([num2str(multi_sin_num),'音干扰信号频谱']);
case 3 %%%%%%%%%%% 噪声调频干扰 %%%%%%%%%%
for i = 1:Jam_ch_num
f_jam = rand(signal_len,1)*Bs - Bs/2;
Jam = Jam + amod(f_jam,fh+fm+(channel(i)-K/2-1/2)*Bs,fsample,'fm');
end
Jam = (Jam - mean(Jam))/std(Jam);
figure,plot((0:signal_len-1)/(signal_len)*fsample,abs(fft(Jam))),grid on,title('噪声调频干扰信号频谱');
case 4 %%%%%%%%%%% MFSK 干扰 %%%%%%%%%%
for i = 1:Jam_ch_num
Jam = Jam + DMOD(randsrc(Data_len,1,(0:Jam_M-1)),fm+fh+(channel(i)-K/2-1/2)*Bs, fs, fsample,'fsk', Jam_M, Bs/Jam_M);
end
Jam = (Jam - mean(Jam))/std(Jam);
figure,plot((0:signal_len-1)/(signal_len)*fsample,abs(fft(Jam))),grid on,title([num2str(Jam_M),'FSK干扰信号频谱']);
otherwise %%%%%%%%%%% 无人为干扰 %%%%%%%%%%
end
Jam = Jam*10^(-SJR/20);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%% 跳频信号接收 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%% 设接收系统与接收信号严格同步 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Rt = awgn(St,snr) + Jam; % 接收信号
figure
plot((0:signal_len-1)/(signal_len)*fsample,abs(fft(Rt))),grid on,title('接收信号频谱');
%%% 接收参数设置
N1 = 48; % 宽带带通滤波器阶数
wide_fir_coff = fir1(N1,[2*fh/fsample,2*(fh+2*fm)/fsample]); % 接收机宽带带通滤波器系数
N2 = 48; % 宽带低通滤波器阶数
lowpass_fir_coff = fir1(N2,4*fm/fsample); % 解跳后宽带低通滤波器系数
N3 = 96; % 窄带带通滤波器阶数
bandpass_fir_coff = fir1(N3,[0.22,0.28]); % 降采样后窄带带通滤波器系数
%%%%%%%%%%%%%%%%%%% 接收信号通过宽带带通滤波器 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Rt_passband = zeros(signal_len,1); % 通过宽带滤波器后的信号
for i = 1:N1/2
Rt_passband(i) = wide_fir_coff * [zeros(N1/2-i+1,1);Rt(1:N1/2+i)];
end
for i = (N1/2+1):(signal_len - N1/2)
Rt_passband(i) = wide_fir_coff * Rt(i-N1/2:N1/2+i);
end
for i = (signal_len - N1/2 + 1):signal_len
Rt_passband(i) = wide_fir_coff * [Rt(i-N1/2:signal_len);zeros(i+N1/2-signal_len,1)];
end
% figure
% plot((0:signal_len-1)/(signal_len)*fsample,abs(fft(Rt_passband))),grid on,title('接收信号宽带滤波后频谱');
%%%%%%%%%%%%%%%%%%% 本地跳频载波产生 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FH_sin = zeros(signal_len,1); % 本地跳频信号载波
phase = 2*pi*rand;
for i = 1:ceil(signal_len/fsample/Tc)
f2 = fh + (FH_seq(i)*2 - (K-1))*Bs/2; % 跳频频点中心频率
FH_sin((i-1)*fsample*Tc + 1:i*fsample*Tc) = cos(2*pi*f2*(0:fsample*Tc-1)/fsample + phase);
phase = 2*pi*rand; % 随机相位(非相干慢跳频)
% phase = phase + 2*pi*f*(fsample*Tc)/fsample; % 连续相位(相干慢跳频)
end
FH_sin(signal_len+1:end) = [];
%%%%%%%%%%%%%%%%%%% 解跳 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Rt_mix_fh = Rt_passband.*FH_sin; % 接收信号与本地跳频信号混频
figure
plot((0:signal_len-1)/(signal_len)*fsample,abs(fft(Rt_mix_fh))),grid on,title('解跳混频后信号频谱');
%%%%%%%%%%%%%%%%%%% 解跳信号通过宽带低通滤波器 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Rt_lowpass = zeros(signal_len,1); % 通过宽带低通滤波器后的信号
for i = 1:N2/2
Rt_lowpass(i) = lowpass_fir_coff * [zeros(N2/2-i+1,1);Rt_mix_fh(1:N2/2+i)];
end
for i = (N2/2+1):(signal_len - N2/2)
Rt_lowpass(i) = lowpass_fir_coff * Rt_mix_fh(i-N2/2:N2/2+i);
end
for i = (signal_len - N2/2 + 1):signal_len
Rt_lowpass(i) = lowpass_fir_coff * [Rt_mix_fh(i-N2/2:signal_len);zeros(i+N2/2-signal_len,1)];
end
figure
plot((0:signal_len-1)/(signal_len)*fsample,abs(fft(Rt_lowpass))),grid on,title('解跳混频去除倍频信号频谱');
%%%%%%%%%%%%%%%%%%% 采样 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
sample_rate = fm*8; % 8 倍载波采样速率
Rt_bassband = Rt_lowpass(1:fsample/sample_rate:end); % 基带MFSK信号(降采样)
sample_len = length(Rt_bassband);
figure
plot((0:sample_len-1)/(sample_len)*sample_rate,abs(fft(Rt_bassband))),grid on,title('基带采样信号频谱');
%%%%%%%%%%%%%%%%%%% 窄带滤波 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Rt_baseband = zeros(sample_len,1);
for i = 1:N3/2
Rt_baseband(i) = bandpass_fir_coff * [zeros(N3/2-i+1,1);Rt_bassband(1:N3/2+i)];
end
for i = (N3/2+1):(sample_len - N3/2)
Rt_baseband(i) = bandpass_fir_coff * Rt_bassband(i-N3/2:N3/2+i);
end
for i = (signal_len - N3/2 + 1):sample_len
Rt_baseband(i) = bandpass_fir_coff * [Rt_bassband(i-N3/2:sample_len);zeros(i+N3/2-sample_len,1)];
end
figure
plot((0:sample_len-1)/(sample_len)*sample_rate,abs(fft(Rt_baseband))),grid on,title('窄带滤波后基带信号频谱');
%%%%%%%%%%%%%%%%%% MFSK 信号解调 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Rdata = DDEMOD(Rt_baseband, fm, fs, sample_rate, 'fsk/noncoherence',M);
error = length(find(Data ~= Rdata))/length(Data)*100; % 误码率
figure
subplot(311),plot(Data),grid on,title('发送数据');
subplot(312),plot(Rdata),grid on,title('接收数据');
subplot(313),plot(Data-Rdata),grid on,title(['误码率 = ',num2str(error),'%']);