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# ifilter: Interactive Fourier filter function 3

Date Added: June 19, 2013  |  Visits: 221

ifilter(x,y) or ifilter(y) or ifilter([x y]) or ry=ifilter(x,y,center,width,shape,plotmode,filtermode)Keyboard-operated interactive Fourier filter function for time-series signal (x,y), with keyboard controls that allow you to adjust the filter parameters continuously while observing the effect on your signal dynamically. Optinal input arguments set the intital values of center frequency, filter width, shape, plotmode (1=linear; 2=semilog frequency; 3=semilog amplitude; 4=log-log) and filtermode ('Band-pass','Lowpass', 'Highpass', 'Bandpass', and 'Band-reject (notch)'). Returns the filtered signal. Press K to list keyboard commands.T. C. O'Haver (toh@umd.edu), Version 3 adds X key to switch between frequency and period x scale on power spectrum plot. Example 1: x=0:100;y=sin(x);ifilter(x,y); Example 2 uses optional input arguments to set intital values: x=0:(1/8000):.3; y=(1+12/100.*sin(2*47*pi.*x)).*sin(880*pi.*x)+(1+12/100.*si(2*20*pi.*x)).*sin(2000*pi.*x); ry=ifilter(x,y,132,31,18,3,'Band-pass'); KEYBOARD CONTROLS when figure window is topmost: Adjust center frequency.......Coarse: < and > Fine: left and right cursor arrows Adjust filter width...........Coarse: / and " Fine: up and down cursor arrows Filter shape..................A,Z (A more rectangular, Z more Gaussian) Filter mode...................B=bandpass; N or R=notch (band reject) H=High-pass; L=Low-pass Select plot mode..............1=linear; 2=semilog frequency 3=semilog amplitude; 4=log-log Print keyboard commands.......K Pints this list Print filter parameters.......Q Prints input argumentsy: center,width,shape,plotmode,filtermode Print current settings........T Prints list of current settings Switch SPECTRUM X-axis scale..X switch between frequency and period x scale on POWER SPECTRA Switch OUTPUT Y-axis scale....Y switch between fixed or variable y scale on output plot Play output as sound..........P or Enter Save output as .mat file......S

 Requirements: No special requirements Platforms: Matlab Keyword: Arrows,  Cursor,  Dhighpass,  Dlowpass,  Filter,  Gaussian,  Ifilter,  Rectangular,  Reject,  Shapeaz,  Widthcoarse Users rating: 0/10