Extracts the harmonic component of the Signal at angular frequency Wtrue. Can be used as sinusoid amplitude and phase estimator if frequency is known or as a narrowband filter extracting particular frequency component from the signal. Equivalent to Fourier transform, just frequency is not limited to Fourier bins.
Uses sine wave correlation (SWC). More details in:
L.Svilainis, et al. The Automated Complex Impedance Measurement System. Electronics and Electrical Engineering. 2007. Nr. 4(76),pp. 59-62. Available at: http://eejournal.ktu.lt/index.php/elt/article/view/10720
Other m-files required: none
Subfunctions: none
MAT-files required: none
Authors: Linas Svilainis
Kaunas University of Technology, Dept. of Electronics Engineering,
Kaunas, Lithuania
email address: linas.svilainis@ktu.lt
December 2006; Last revision: 10-Jul-2018
Copyright: Linas Svilainis
Syntax: [U] = SWCtruncated(t,Wtrue,Signal)
Inputs:
Signal - (1,N) array of sampled signal values
t - time axis,(1,N) array, must be same length as Signal
Wtrue - angular frequency for estimation (2*pi*F)
Outputs:
U - measured complex amplitude of the sinusoid
Notes:
The more periods you record the better is noise or other frequencies rejection, the better estimation accuracy;
Recond length is truncated to aproximately fit the integer number of frequency Wtrue periods;
Time axis t must be sampled equally;
Example (TestSWC)
clear all
fsampl=100e6;%sampling frequency is 100MHz
f0=1.3012e6;%sinusoid frequency is 1.3012MHz
phi=30/180*pi;%sinusoid phase is 30deg
Um=0.141;%sinusoid amplitude is 0.141V
N=100;%record length is 1000 samples
%make time axis:
t=(0:(N-1))/fsampl;
%generate test signal:
MySignal=Um*cos(2*pi*f0*t+phi);
%add some noise:
MySignal=MySignal+0.01*randn(1,N);
%estimate signal amplitude and phase:
Uest = SWCtruncated(t,2*pi*f0,MySignal);
Umag=abs(Uest)
Uph_rad=angle(Uest)
Uph_deg=Uph_rad/pi*180
%plot the raw signal and estimated harmonic component:
figure(1)
plot(t*1e6,MySignal,'r',t*1e6,Umag*cos(2*pi*f0*t+Uph_rad),'k')
xlabel('Time, us')
ylabel('Amplitude, V')
grid on
axis tight
引用格式
Linas Svilainis (2024). SWCtruncated (https://www.mathworks.com/matlabcentral/fileexchange/68174-swctruncated), MATLAB Central File Exchange. 检索时间: .
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