alice@0: function [output]=createFiltNoise(input,centreFreq,bandWidth,filterOrder,Fs)
alice@0: 
alice@0: % create filtered noise for bandwidth simulation
alice@0: %
alice@0: % Input:
alice@0: %   - input: input to be filtered
alice@0: %   - centreFreq: centre frequency or cutoff frequency
alice@0: %   - bandWidth: width of filter
alice@0: %   - filterOrder: order of butterworth filter (4)
alice@0: %   - Fs: sampling frequency (44100)
alice@0: %
alice@0: % Output:
alice@0: %   - output: array
alice@0: %
alice@0: 
alice@0: % Developer:  - Alice Clifford (alice.clifford@eecs.qmul.ac.uk)
alice@0: 
alice@0: 
alice@0: 
alice@0: if centreFreq==0  %LOW PASS FILTER FOR CENTRE FREQ ==0
alice@0:     
alice@0:     cutoffFreq=bandWidth;
alice@0:     
alice@0:     normCutFreq=(cutoffFreq/(Fs/2));
alice@0:     
alice@0:     [b,a]=butter(filterOrder,normCutFreq,'low');
alice@0:     
alice@0:     output=filter(b,a,input);
alice@0:     
alice@0:     
alice@0:     
alice@0: elseif centreFreq==22050 %HIGH PASS FILTER FOR CENTREFREQ == FS/2
alice@0:     
alice@0:     cutoffFreq=(Fs/2)-bandWidth;
alice@0:     
alice@0:     normCutFreq=(cutoffFreq/(Fs/2));
alice@0:     
alice@0:     [b,a]=butter(filterOrder,normCutFreq,'high'); %HIGH PASS FILTER
alice@0:     
alice@0:     output=filter(b,a,input);
alice@0:     
alice@0:     
alice@0:     
alice@0:     
alice@0: else% %BAND PASS - NEED LOW AND HIGH PASS
alice@0:     
alice@0:     lowBandFreq=centreFreq-(bandWidth/2);
alice@0:     highBandFreq=centreFreq+(bandWidth/2);
alice@0:     
alice@0:     highNormBandFreq=(highBandFreq/(Fs/2));
alice@0:     lowNormBandFreq=(lowBandFreq/(Fs/2));
alice@0:     
alice@0:     
alice@0:     [b,a]=butter(filterOrder,[lowNormBandFreq highNormBandFreq]);
alice@0:     
alice@0:     
alice@0:     
alice@0:     output=filter(b,a,input);
alice@0:     
alice@0: end