⛄1. Digital bandpass transmission system
The transmission mode of digital signal is divided into baseband transmission (baseband transmission) and bandpass transmission (bandpass transmission). Previous blog Digital baseband transmission system - digital baseband signal has a simple understanding of baseband transmission. However, most channels in practice (such as wireless channels) cannot directly transmit baseband signals because of their bandpass properties, because digital baseband signals often have rich low-frequency components. In order to transmit a digital signal in a bandpass channel, the carrier must be modulated with a digital baseband signal to match the signal to the characteristics of the channel. This process of controlling the carrier with a digital baseband signal and converting the digital baseband signal into a digital bandpass signal (modulated signal) is called digital modulation. The process of restoring the bandpass signal to a digital baseband signal through a demodulator at the receiving end is called digital demodulation. A digital transmission system including modulation and demodulation processes is usually called a digital bandpass transmission system.
⛄ 2. Part of the source code
clear all;
clc;
I=imread('star.jpg');
Imgray=rgb2gray(I);
thresh=graythresh(I); % gray threshold
Im=im2bw(I,thresh);
Im2=im2double(Im); %Convert logical value to double precision
P0=Mybsc(Im,0);
P0_1=Mybsc(Im,0.1);
P0_2=Mybsc(Im,0.2);
P0_5=Mybsc(Im,0.5);
P1=Mybsc(Im,0.5); 1);
figure
subplot(2,2,1);imshow(I,[]);title('Original image');
subplot(2,2,2);imshow(Imgray,[]);title('gray degree map');
subplot(2,2,3);imshow(Im2,[]);title('binary image');
subplot(2,2,4);imshow(P0,[]);title( 'BSC channel through p=0 (noise-free channel)');
figure
subplot(2,2,1);imshow(P0_1,[]);title('BSC channel through p=0.1');
subplot(2 ,2,2);imshow(P0_2,[]);title('BSC channel with p=0.2');
subplot(2,2,3);imshow(P0_5,[]);title('BSC channel with p=0.5'); subplot
(2,2,4);imshow(P1,[]);title(' After p=1 BSC channel (noise-free channel)');
⛄3. Running results
⛄4. Matlab version and references
1 matlab version
2014a
2 References
[1] Gao Yanyan, Zhang Jing, Li Li, Jia Yingqian. Design of GUI-based Teaching Demonstration System for "Digital Signal Processing" [J]. Education Teaching Forum. 2019, (48) [2] Li Jun, Zhang
Shuling , Shuai Jing. Digital Signal Processing Auxiliary Teaching System Based on Matlab GUI Interface [J]. Information Communication. 2020, (08) [3] Zhu Yukang.
Digital Signal Processing Experimental Platform Based on MATLAB [J]. Communication Power Technology. 2021, 38(03)
3 Remarks
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