完整的BPSK源码程序 - matlab通信信号

下载频道> 资源分类> matlab源码> 通信信号> 完整的BPSK源码程序

标题：完整的BPSK源码程序
分享到：

所属分类: 通信信号资源类型：文件大小: 5 KB 上传时间: 2016-01-25 20:00:31 下载次数: 6 资源积分：1分提供者: xiaopeng2 完整的BPSK源码程序

内容：
完整的BPSK源码程序，程序员在编程的过程中可以参考学习使用，希望对IT程序员有用，此源码程序简单易懂、方便阅读，有很好的学习价值！

%**************************************************************************

% DIGITAL COMMUNICATION SYSTEM

% BPSK MODEL

%**************************************************************************

%IMORTANT VARIABLES USED

%t - Modeled system time

%fm - Main frequency of message signal

%harm - Frequency components of the message signal

%amp - Amplitude of the corresonding harmonic frequency component

%sampling_rate - System sampling rate . Default rate is 20 samples per cycle of maximum freqency component

%range - Range of the time sampling is done . Default range is 2 cycles of minimum frequncy component

%msg - Message signal to be trasnmitted

%minamp - Minimum amplitude that can be used in this model

%n_sample - Number of samples per cycle of the message signal

%fs - Sampling frequency for sampling the message signal

%msamp - Sampled version of the message signale with sampling frequency fs

%no_of_levels - Number of quantization levels

%quantile - Quantile interval

%code - Representation levels

%mq - Quantization output of sampled message signal

%mq1 - Sampled version of quantized sample message signal

%bits - Binary sequence of sampled quantized signal (output of ADC)

%fc - Carrier signal frequency

%nsamp - System Samples per cycle of carrier signal

%ncyc - Number of cycles of carrier signal for one bit interval

%tb - Bit interval

%t_tran - Total transmission time , in order to find diffrence between already existing time variable 't' see Note-1

%mod_sig - BPSK modulated carrier signal

%tran_sig - Siganl after transmission through AWGN channel , so that Awg noise is added with the original transmitted signal

%f_freq - Frequency range used for visualising FFT of the signal

%f_tran - Noise added transmitted signal representation in frequency domain

%f_rece - Received signal after removing noise ,in frequency domain

%dec_data - Binaray data extracted from BPSK modulated carrier signal

%mq_rece - Decoded sampled quantized message signal data calculated from extracted binary sequence

%f_out - Reconstruted signal in frequency domain after filtering

%out - Reconstruted signal from the received signal ,in time domain i.e, output of the receiver

%gain - gain of the amplifier expressed in ratio not in db

%ABBREVATIONS

%ADC - Analog to Digital Convertor

% Converts analog signal to digital signal

%AWGN - Anti-White Gaussian Noise

% A channel model with zero mean noise , commonly used channel model .

%DAC - Digital to Analog Convertor

% Converts digital signal to analog signal

%Rx - Receiver

%Tx - Transmitter

%*****************************-TRANSMITTER-********************************

clear all;

clc;

%MESSAGE SIGNAL PARAMETERS

fm=1e3; %Main frequency of message signal

harm=[ 1 0.5 2 1 ]; %Frequency components of the message signal

%In this model the message signal is represented by fourier sine series

amp=[ 1 2 3 1 ]; %Amplitude of the corresonding harmonic frequency component

sampling_rate=1/(20*max(fm*harm)); %System sampling rate . Default rate is 20 samples per cycle of maximum freqency component

range=2/min(fm*harm); %Range of the time sampling is done . Default range is 2 cycles of minimum frequncy component

t=0:sampling_rate:range; %System timing

%MESSAGE SIGNAL

msg=zeros(size(t));

for k=1:length(harm)

msg=msg+amp(k)*sin(2*pi*harm(k)*fm*t);

end

minamp=min(msg); %Minimum amplitude that can be used in this model . Normally ,it need to be kept as a global constant

%But for flexibility of program it is made here as variable depending on message signal value

%SAMPLING

n_sample=5;

fs=n_sample*max(harm*fm); %Sampling ferqency .

msamp=zeros(size(msg));

msamp(1:1/(fs*sampling_rate):length(t))=msg(1:1/(sampling_rate*fs):length(t)); %Sampled output signal

figure(1);plot(t,msg); grid on

hold on

stem(t,msamp);

xlabel('time');ylabel('Message signal,Sampled signal and Quantized signal');

title('MESSAGE SIGNAL , SAMPLED MESSAGE SIGNAL AND QUANTIZED SIGNAL');

legend('Message signal','Sampled Signal','Quantized Signal');

%QUANTIZATION

no_of_levels=4; %Number of quantization levels

quantile=(max(msamp)-min(msamp))/(no_of_levels); %Quantile interval

code=min(msamp):quantile:max(msamp); %Representation levels

mq=zeros(size(msamp));

for k=1:length(code)

values=(( msamp>(code(k)-quantile/2) & msamp<(code(k)+quantile/2)));

mq(values)=round(code(k)); %Quantization output of sampled message signal

end

clear values;

stem(t,mq,'r*');grid on

legend('Message signal','Sampled Signal','Quantized Signal');

%ENCODING

if min(mq)>=0

minamp=0;

end

mq1=mq-round(minamp); %Shifting negative values to postive side for conversion to binary and sampling

%quantized message signal

bits=de2bi(mq1(1:1/(fs*sampling_rate):length(mq)),4,'left-msb')';

bits=bits(:)'; %ADC - Generating binary sequence of sampled quantized signal

figure(5);stem(bits,'*r');hold on;

legend('Bit sequence in Transmitter','Bit sequence in Receiver');

%PASS BAND MODULATION (BPSK)

fc=1e6; %Carrier signal frequency

nsamp=10; %System Samples per cycle of carrier signal

ncyc=2; %Number of cycles of carrier signal for one bit interval

tb=0:1/(nsamp*fc):ncyc/fc; %Bit interval

t_tran=0:1/(nsamp*fc):(ncyc*length(bits))/fc+(length(bits)-1)/(nsamp*fc); %Total transmission time

mod_sig=zeros(size(t_tran));

l=1;

for k=1:length(tb):length(mod_sig)

if(bits(l)==1)

mod_sig(k:k+length(tb)-1)=cos(2*pi*fc*tb); %Phase Modulation of carrier for repesenting binary symbol one

else

mod_sig(k:k+length(tb)-1)=-cos(2*pi*fc*tb); %Phase Modulation of carrier for repesenting binary symbol zero

end

l=l+1;

end

%**********************AWGN-CHANNEL****************************************

tran_sig=awgn(mod_sig,10); %Transmisson of modulated carrier signal through AWGN channel

figure(2);plot(t_tran,mod_sig,'.-b',t_tran,tran_sig,'r');

axis([0 3*ncyc/fc -2 2]);

xlabel('time');ylabel('Tx signal and Tx signal with noise');

title('TRANSMITTED SIGNAL AND NOISE ADDED TRANSMITTED SIGNAL');

legend('Transmitted signal','Transmitted signal with noise added');

%*************************RECEIVER*****************************************

%Filter

f_freq=-(nsamp*fc)/2:(nsamp*fc)/length(t_tran):(nsamp*fc)/2-(nsamp*fc)/length(t_tran); %Frequency range used for

%visualising FFT of the signal

f_tran=fft(tran_sig); %FFT of f

figure(3);plot(f_freq,fftshift(f_tran),f_freq,fftshift(fft(mod_sig)),'g');grid on;

xlabel('Frequency');ylabel('Signal Amplitude');

legend('Modulated Signal','Received Signal');

title('MODULATED SIGNAL VS RECEIVED SIGNAL IN FREQUENCY DOMAIN');

f_rece=zeros(size(f_tran));

fir=(f_freq < -3*fc | f_freq>3*fc);

f_rece(fir)=f_tran(fir); %Filtering noisy signal in

f_rece(~fir)=0.5*f_tran(~fir); %frequnecy domain to remove noise

t_rece=ifft(f_rece); %Noise removed signal

figure(4);plot(t_tran,t_rece);grid on;

xlabel('time');ylabel('Received Signal');

title('RECEIVED SIGNAL AFTER NOISE IS FILTERED');

delete f_freq f_tran f_rece;

clear f_freq f_tran f_rece;

%Demodulation

dec_data=zeros(size(bits));

l=1;

for k=1:length(tb):length(t_tran) %Extracting binary data from carrier using correlation method

a=corrcoef(cos(2*pi*fc*tb),t_rece(k:k+length(tb)-1));

b=mean(real(a(:)));

if b>0.5

dec_data(l)=1;

else

dec_data(l)=0;

end

l=l+1;

end

figure(5);stem(dec_data);grid on;

xlabel('Bit position');ylabel('Bit sequence in Recevier and Transmitter');

title('BIT SEQUENCE IN RECEIVER Vs TRANSMITTER');

legend('Bit sequence in Transmitter','Bit sequence in Receiver');

%DECODING

dec_data=reshape(dec_data,4,length(bits)/4)';

mq_rece=zeros(size(mq));

mq_rece(1:1/(fs*sampling_rate):length(mq))=bi2de(dec_data,'left-msb')'+min(mq); %DAC - Extracting sampled quantized data from decoded binary sequence

%SIGNAL RECONSTRUCTION

f_freq=-1/(2*sampling_rate):1/(sampling_rate*length(t)):1/(2*sampling_rate)-1/(sampling_rate*length(t));

f_rece=fft(mq_rece); %FFT of received extracted sampled quantized signal

f_out=zeros(size(f_rece));

figure(6);plot(f_freq,fftshift(f_rece),f_freq,fftshift((fft(msg))));grid on;

xlabel('frequency');ylabel('FT-msg and FT-Received signal');

title('ORIGINAL SIGNAL Vs RECEIVER OUTPUT IN FREQUENCY DOMAIN');

legend('Receiver output','Original signal');

f_out((f_freq < -17000 | f_freq > 17000))=f_rece((f_freq < -17000 | f_freq > 17000)); %Filtering in frequency domain for reconstruction of signal from sampled

%quantized data

out=ifft(f_out); %Reconstructed output signal

figure(7);plot(t,4*out,t,msg,'r');grid on;

xlabel('time');ylabel('msg-sig and Rx-output');

title('ORIGINAL SIGNAL Vs RECEIVER OUTPUT');

legend('Receiver output','Original signal');

gain=4; %Gain of amplifier (simple ratio not in db)

out=out*gain; %Output after amplification

figure(8);plot(t,out);grid on;

xlabel('time');ylabel('Receiver output');

title('RECEIVER OUTPUT');

%clear all;

clc;

%NOTE

% 1)The progrma contains two time variables t and t_tran

% i)The first time variable(t) represents the continuous

% real time of the modeled system as the system is modeled

% using the deveice (i.e., laptop or computer) which cannot

% process data at infinite resolution

% ii)The second time varible(t_tran) reprsents the total time

% interval needed for the carrier signal to carry all the

% binary data

% 2)The frequency specification mention in this model is not exact

% as the fourier trasformed signals are not shifted to center.

% So , the filtered used in this model seem like highpass

% filter , but as the frequency domain converted signal is not

% centered at the origin ,therefore the filters are lowpass

% filters .

% 3)Filter in this model is done by removing directly the

% unwanted frequency component in frequency domain , which helps

% in understanding the concept of filtreing even though it is

% not practical

文件列表（点击上边下载按钮，如果是垃圾文件请在下面评价差评或者投诉）:

完整的BPSK源码程序/
完整的BPSK源码程序/BPSK_complete_model/
完整的BPSK源码程序/BPSK_complete_model/BPSK_complete_model.m
完整的BPSK源码程序/BPSK_complete_model/license.txt

关键词：源码 程序

matlab源码下载排行

回到顶部

友情链接

matlab源码网站源码编程语言网络编程手机通讯编程 KUNAG 官网 KUNAG 电商更多

: 联系方式| 版权声明| 招聘信息| 广告服务| 银行汇款| 法律顾问| 兼职技术| 付款方式| 关于我们|; 网站客服程序员兼职招聘 411241577@qq.com; 沪ICP备19040327号-3; 公安备案号：沪公网安备 31011802003874号; 库纳格流体控制系统（上海）有限公司版权所有; Copyright © 1999-2014, GUSUCODE.COM, All Rights Reserved

关键词： 源码 程序

相关推荐

matlab源码下载排行

友情链接

关键词：源码程序