plot binary vs time

Question

Aswas 2018-8-3

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/413392-plot-binary-vs-time

回答： Guillaume 2018-8-3

Hi, I have 1's and 0's but want 1's to be plotted as a positive number and o's as negative number:

Code:

if(z>0)                
    a=1;
else
    a=0;
end
mn=[t1 a];

2 个评论
显示无隐藏无

Guillaume 2018-8-3

"want 1's to be plotted as a positive number"

Which number? +1?

"and o's as negative number"

Which number? -1?

The code snippet you show makes no sense at all and is not commented so we have no idea what its intent is.

Aswas 2018-8-3

编辑：Guillaume 2018-8-3

在 MATLAB Online 中打开

It is for PSK demodulation, and yes, -1 and + 1....

% Binary PSK demodulation 
mn=[];
for n=ss:ss:length(m)
    t=bp/99:bp/99:bp;
    y=A*(sin(2*pi*f*t2+pi))%+(sin(2*pi*f*t+pi));  
%y=sin(2*pi*f*t)for 0 deg shift;  % carrier signal 
    mm=y.*m((n-(ss-1)):n);% mm=y.*m((n-(ss-1)):n)
    t4=bp/99:bp/99:bp;
    z=trapz(t4,mm)       % intregation method
    zz=round((2*z/bp)) 
    if(zz>0)                 
      a=1;
    else
     a=0;
    end
    mn=[mn a];
  end
  disp(' Binary information at Reciver :');
  disp(mn);

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Guillaume 2018-8-3

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/413392-plot-binary-vs-time#answer_331455

在 MATLAB Online 中打开

If you want +1 and -1, why don't you store that in the first place in your vector instead of 1/0?

if zz > 0
   a = 1;
else
   a = -1;
end

Why go use 0 if you want -1?. If you really do want to do it afterwards for some reason:

%after the loop
mn(mn == 0) = -1;

By the way, there's a lot of variable that get recreated each step of the loop but never change ( t, y, t4). These should be calculated once before the loop. You're just wasting time recalculating the same thing over and over.

Also, the way you construct you mn is very awkward and slow as it gets resized a every step of the loop. Preallocation and indexing would be faster:

%stuff that doesn't need to be calculated in the loop
t=bp/99:bp/99:bp;
y=A*(sin(2*pi*f*t2+pi))%+(sin(2*pi*f*t+pi));  
t4=bp/99:bp/99:bp;
%loop preparation,
v = ss:ss:length(m);
mn = zeros(1, numel(v);  %preallocation
%loop
for idx = 1:numel(v)
   n = v(idx);
   mm=y.*m((n-(ss-1)):n);% mm=y.*m((n-(ss-1)):n);
   z=trapz(t4,mm);       % intregation method
   zz=round((2*z/bp));
   if zz > 0
     mn(idx) = 1;
   else
     mn(idx) = -1;  %or 0 if you really must
   end
 end
 plot(mn);