notch filter to remove 50Hz fundamental frequency and its second (100 Hz) and third (150Hz) harmonics. with using filter(),

My code is down below I get the error like this Not enough input arguments. Error in ecg (line 22 ) d = round(d0 * L / d0(15)); % Scale them to fit in length L.

How can I fix this please help me

lz

oad ecg.mat; % Load noisy ECG recording
%Bandpass filter

fs = 500; % Sampling rate

T = 1/500; % Sampling interval

b1 =[0.9765   -1.5800    0.9765]; %Notch filter with a notch frequency of 50 Hz

a1 =[1.0000   -1.5774    0.9504];

b2 =[0.9753   -0.6028    0.9753]; % Notch filter with a notch frequency 100 Hz

a2 =[1.0000   -0.6025    0.9504];

b3 =[0.9751    0.6027    0.9751]; % Notch filter with a notch frequency of 150 Hz

a3 =[1.0000    0.6025    0.9504];

y1 = filter(b1,a1,ecg); % First section filtering

y2 = filter(b2,a2,y1); % Second section filtering

y3 = filter(b3,a3,y2); % Third section filtering

Answer 1

[Daniel M]

'ecg' is the name of a function in the example:

MATLAB/Examples/R2019a/dsp/FindHeartRateUsingPeakFinderPanelWithECGInputSignalExample/ecg.m

If 'ecg.mat' is also the name of a file of yours, I suggest loading it in as follows:

data = load('ecg.mat');
ecg = data.ecg; % if the name of the variable actually IS ecg

Otherwise, I have not looked at the code you're using to create filters. Let me know if there are problems with that and I'll take a closer look.

[nrgsn]

It didn't work .I changed ecg to signalNoise(I used whos command to find it) then it worked without error but this time my plots are wrong.I am posting code with plot command could you tell me what is the problem?Is it filtering or something else?

clear
clc
load ecg.mat; % Load noisy ECG recording
x=signalNoise;
L=length(x);
fs = 500; % Sampling rate
T = 1/500; % Sampling interval
t =(0:L-1)*T;        % Time vector


b1 =[0.9765   -1.5800    0.9765]; %Notch filter with a notch frequency of 50 Hz

a1 =[1.0000   -1.5774    0.9504];

b2 =[0.9753   -0.6028    0.9753]; % Notch filter with a notch frequency 100 Hz

a2 =[1.0000   -0.6025    0.9504];

b3 =[0.9751    0.6027    0.9751]; % Notch filter with a notch frequency of 150 Hz

a3 =[1.0000    0.6025    0.9504];

y1 = filter(b1,a1,x); % First section filtering


y2 = filter(b2,a2,y1); % Second section filtering

y3 = filter(b3,a3,y2); % Third section filtering

% BLT design

wd1 = 2*pi*0.25;

wd2 = 2*pi*40;

wa1 =(2/T)*tan(wd1*T/2);

wa2 =(2/T)*tan(wd2*T/2);

[B,A]=lp2bp([1.4314], [1 1.4652 1.5162],sqrt(wa1*wa2),wa2-wa1);

[b,a]=bilinear(B,A,fs);

b =[ 0.046361 0 -0.092722 0 0.046361];

a =[1 -3.352292 4.255671 -2.453965 0.550587];

y4 = filter(b,a,y3); %Bandpass filtering



subplot(3,1,1);plot(t,signalNoise);grid;ylabel('(a)');

subplot(3,1,2);plot(t,y3);grid;ylabel('(b)');

subplot(3,1,3);plot(t,y4);grid;ylabel('(c)');

xlabel('Time (sec.)');

[Daniel M]

I don't have your data.

Answer 2

[Sabbir Ahmed]

Hi, May I know how you got the notch filter's coefficient for different noise section?