How to do signal processing for discrete set of data
4 次查看(过去 30 天)
显示 更早的评论
I've a amplitude-time signal data with 10000 data points having a sampling period of 0.5 microseconds. It has noise embedded in it. I want to remove the noise and do signal averaging. I'm completely new to signal processing and matlab. I've no idea which filter to use also. Can somebody help me with it?
0 个评论
采纳的回答
Star Strider
2017-1-15
The data you provided only has 256 data points. It does not have much noise, and no significant baseline drift, so I used a lowpass FIR filter here.
This works:
[d,s,r] = xlsread('Athira Surendran data.xls');
Ts = 0.5; % Sampling Interval (s)
Fs = 1/Ts; % Sampling Frequency (Hz)
Fn = Fs/2; % Nyquist Frequency (Hz)
sig = d(1,:); % Signal
t = d(3,:); % Time
L = length(t);
figure(1)
plot(t, sig)
grid
xlabel('Time')
ylabel('Amplitude')
FTsig = fft(sig)/L;
Fv = linspace(0, 1, fix(L/2)+1)*Fn;
Iv = 1:length(Fv);
figure(2)
plot(Fv, abs(FTsig(Iv))*2)
grid
xlabel('Frequency (Hz)')
ylabel('Amplitude')
fcuts = [0.08 0.19]; % Frequency Vector
mags = [1 0]; % Magnitude (Defines Passbands & Stopbands)
devs = [0.01 0.05]; % Allowable Deviations
[n,Wn,beta,ftype] = kaiserord(fcuts,mags,devs,Fs); % Kaiser Window
n = n + rem(n,2);
hh = fir1(n,Wn,ftype,kaiser(n+1,beta),'scale'); % Desing FIR Lowpass Filter
figure(3)
freqz(hh, 1, 2^14, Fs) % Plot Filter Characteristic
filt_sig = filtfilt(hh, 1, sig); % Filter Signal
figure(4)
plot(t, sig, ':b', 'LineWidth',1.5)
hold on
plot(t, filt_sig, '-r')
hold off
grid
legend('Original', 'Low-Pass Filtered')
xlabel('Time')
ylabel('Amplitude')
更多回答(0 个)
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Kaiser 的更多信息
产品
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!