how to solve repeated y-axis problem

function [t_est,f_est]=threeDFT(v,fs,tmax,N0)
% v : volt as function of time
% fs : sampling frequency (Hz)
% tmax : time of final estimation
% N0 : number of samples in the window
% to test: [t,f]=threeDFT(@(t)(220*sin(2*pi*50.1*t+pi/2)),50*512,1,512)
% to test: [t,f]=threeDFT(@(t)(220*sin(2*pi*50.1*t+pi/2)+randn(size(t))*.1),50*512,1,512)
fs=200; %sampling freq.
dt =1/fs;
N0=fs/50; %number of samples/cycle
m=3; %no. of cycles
t = dt*(0:200); %data window
fi=50; %Frequency test
v = @(t)0.5*exp(-1.*t/0.3)+ 2*sin(2*pi*fi*t + pi/6);
figure()
plot(t,v(t))
tmax=1;
n=N0-1:-1:0;
f0=50;
f=50.88;
Hc=2/N0*cos(2*pi*n/N0+pi/N0);
Hs=-2/N0*sin(2*pi*n/N0+pi/N0);
t_est=[];
f_est=[];
j_max=tmax*fs;
for j=1:j_max+1
x=v((j-1:j+N0-2)*dt);
c(j)=x*Hc';
s(j)=x*Hs';
if(j>N0)
Ac(j-N0)=sqrt(sum(c(end-N0+1:end).^2)/N0);
As(j-N0)=sqrt(sum(s(end-N0+1:end).^2)/N0);
cc(j-N0)=c(end-N0+1:end)*Hc';
ss(j-N0)=c(end-N0+1:end)*Hs';
if(j>2*N0)
Acc(j-2*N0)=sqrt(sum(cc(end-N0+1:end).^2)/N0);
Ass(j-2*N0)=sqrt(sum(ss(end-N0+1:end).^2)/N0);
ccc(j-2*N0)=cc(end-N0+1:end)*Hc';
ccs(j-2*N0)=cc(end-N0+1:end)*Hs';
ssc(j-2*N0)=ss(end-N0+1:end)*Hc';
sss(j-2*N0)=ss(end-N0+1:end)*Hs';
ff=f0*N0/pi*atan(tan(pi/N0)*((ccc(j-2*N0).^2+ccs(j-2*N0).^2)./(ssc(j-2*N0).^2+sss(j-2*N0).^2)).^.25);
t_est=[t_est;(j-1)*dt];
f_est=[f_est;ff];
end
end
end
t_est;
f_est
plot(t_est, f_est,'red')
hold on
plot (t,fi)
hold off

3 Comments

Sorry, but what is the problem? All you've done is shared your code. Please explain what the problem is. If there is an error message, copy/paste the entire error message as well (all the red text). Since this is a function, it would also be helpful if you could share what the inputs are that result is your issue, though on closer inspection, all your inputs are immediately overwritten by values inside the function.
the error is in the above fig y-axis repeated value

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Answers (1)

the error in this fig y-axis

2 Comments

I get something slightly different but equivalent.
fs=200; %sampling freq.
dt =1/fs;
N0=fs/50; %number of samples/cycle
m=3; %no. of cycles
t = dt*(0:200); %data window
fi=50; %Frequency test
v = @(t)0.5*exp(-1.*t/0.3)+ 2*sin(2*pi*fi*t + pi/6);
% figure()
% plot(t,v(t))
tmax=1;
n=N0-1:-1:0;
f0=50;
f=50.88;
Hc=2/N0*cos(2*pi*n/N0+pi/N0);
Hs=-2/N0*sin(2*pi*n/N0+pi/N0);
t_est=[];
f_est=[];
j_max=tmax*fs;
for j=1:j_max+1
x=v((j-1:j+N0-2)*dt);
c(j)=x*Hc';
s(j)=x*Hs';
if(j>N0)
Ac(j-N0)=sqrt(sum(c(end-N0+1:end).^2)/N0);
As(j-N0)=sqrt(sum(s(end-N0+1:end).^2)/N0);
cc(j-N0)=c(end-N0+1:end)*Hc';
ss(j-N0)=c(end-N0+1:end)*Hs';
if(j>2*N0)
Acc(j-2*N0)=sqrt(sum(cc(end-N0+1:end).^2)/N0);
Ass(j-2*N0)=sqrt(sum(ss(end-N0+1:end).^2)/N0);
ccc(j-2*N0)=cc(end-N0+1:end)*Hc';
ccs(j-2*N0)=cc(end-N0+1:end)*Hs';
ssc(j-2*N0)=ss(end-N0+1:end)*Hc';
sss(j-2*N0)=ss(end-N0+1:end)*Hs';
ff=f0*N0/pi*atan(tan(pi/N0)*((ccc(j-2*N0).^2+ccs(j-2*N0).^2)./(ssc(j-2*N0).^2+sss(j-2*N0).^2)).^.25);
t_est=[t_est;(j-1)*dt];
f_est=[f_est;ff];
end
end
end
t_est;
f_est
f_est = 193×1
50.0000 50.0000 50.0000 50.0000 50.0000 50.0000 50.0000 50.0000 50.0000 50.0000
plot(t_est, f_est,'red')
% hold on
% plot (t,fi)
% hold off
This is because your values of f_est are all essencially 50
format long
min(f_est)
ans =
49.999999635905169
max(f_est)
ans =
50.000000376435871
sorry how it do in this case

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Asked:

on 5 Dec 2020

Commented:

on 6 Dec 2020

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