317 lines
9.2 KiB
Matlab
317 lines
9.2 KiB
Matlab
classdef Signal
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%SIGNAL Summary of this class goes here
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% Detailed explanation goes here
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properties
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signal
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logbook
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end
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methods
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function obj = Signal(signal)
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%SIGNAL Construct an instance of this class
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% Detailed explanation goes here
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obj.signal = signal;
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SignalType = [];
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TimeStamp = [];
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Length = [];
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SignalPower = [];
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Nase = [];
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Description = [];
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obj.logbook = table(SignalType,TimeStamp,Length,SignalPower,Nase,Description);
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end
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%% CONVERT TO INFORMATIONSIGNAL
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function [i_sig, varargout] = Informationsignal(obj)
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if isa(obj,'Electricalsignal')
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%convert to optical
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varargout{1} = obj.fs;
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i_sig = Informationsignal(obj.signal);
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elseif isa(obj,'Opticalsignal')
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error("Cannot convert from optical- to informationsignal. Use O/E conversion first.");
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end
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end
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%% CONVERT TO Electricalsignal
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function [e_sig, varargout] = Electricalsignal(obj,options)
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arguments
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obj
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options.fs
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options.logbook
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end
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obj.logbook = options.logbook;
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if isa(obj,'Opticalsignal')
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%convert to electrical
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varargout{1} = obj.nase;
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varargout{2} = obj.lambda;
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e_sig = Electricalsignal(obj.signal,"fs",obj.fs,"logbook",obj.logbook);
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elseif isa(obj,'Informationsignal')
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try
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% specify fs at varargin{1}
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e_sig = Electricalsignal(obj.signal,"fs",options.fs,"logbook",options.logbook);
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catch
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error("Signal Conversion failed [I -> E] ");
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end
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end
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end
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%% CONVERT TO Opticalsignal
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function o_sig = Opticalsignal(obj, options)
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arguments
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obj
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options.fs
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options.logbook
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options.nase
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options.lambda
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end
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fn = fieldnames(options);
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for l = 1:numel(fn)
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try
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obj.(fn{l}) = options.(fn{l});
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end
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end
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if isa(obj,'Electricalsignal')
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%convert to optical
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o_sig = Opticalsignal(obj.signal,"fs",obj.fs,"lambda",options.lambda,"logbook",obj.logbook,"nase",options.nase);
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elseif isa(obj,'Informationsignal')
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error("Cannot convert from information- to opticalsignal. Use E/O conversion first.");
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end
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end
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%% Add signals from one signal to another, the first object will sustain
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function Sum = plus(X,Y)
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Sum = X; %first input object will sustain
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Sum.signal = X.signal + Y.signal;
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end
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%% Display length
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function return_length = length(obj)
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%METHOD1 Summary of this method goes here
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% Detailed explanation goes here
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return_length = length(obj.signal);
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end
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%% Write Logbook Entry
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function obj = logbookentry(obj,varargin)
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if nargin > 1
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Description = varargin{1};
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else
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Description = "";
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end
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SignalType = [string(class(obj))];
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TimeStamp = [(datetime('now','TimeZone','local','Format','HH:mm:ss'))];
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Length = [obj.length];
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SignalPower = [obj.power];
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Nase = [0];
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cell = {SignalType , TimeStamp , Length , SignalPower , Nase, Description};
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obj.logbook = [obj.logbook;cell];
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end
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%% Resample Signal
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function obj = resample(obj,options)
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arguments
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obj Signal
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options.fs_in double
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options.fs_out double
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end
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obj.signal = resample(obj.signal,options.fs_out,options.fs_in);
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desc = ['resample signal from ', num2str(options.fs_in*1e-9), ' GHz to ', num2str(options.fs_out*1e-9), ' GHz' ];
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obj = obj.logbookentry(desc);
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end
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%%
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function spectrum(obj,fsamp,options)
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arguments
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obj
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fsamp
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options.figurename = [];
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options.displayname = [];
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end
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%Get figure if there is already a spectrum plot -> I want to add the new
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%spectum "onto" the existing plot to have a better comparison
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if isempty(options.figurename)
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fig = findall(groot, 'Type', 'figure', 'Name', 'power density');
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if isvalid(fig)
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fig = get(fig);
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ax = gca;
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hold on
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else
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figure('name','power density');
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ax = gca;
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end
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else
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fig = findall(groot, 'Type', 'figure', 'Name', options.figurename);
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if isvalid(fig)
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ax = fig.CurrentAxes;
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hold on
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else
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figure('name',options.figurename);
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ax = gca;
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hold on
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end
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end
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%compute FFT of input
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Fsignal = fft(obj.signal);
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%POWER spectral density (todo: toggle?)
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psd = Fsignal.*conj(Fsignal);
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%Use only magnitude of FFT (which was complex)
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psd = abs(psd);
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%Shift the spectrum to yield
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psd = fftshift(psd);
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%divide by N
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psd = psd/length(Fsignal);
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%smoothing
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psd = smooth(psd,1000);
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psd_plot = 20*log10(psd);
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psd_plot(psd_plot<-120) = -120;
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testParseval = 1;
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if testParseval == 1
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E_FreqDomain = sum(psd);
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%test parseval
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E_TimeDomain = sum(abs(Fsignal.^2));
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if isequal(round(E_FreqDomain,1),round(E_TimeDomain,1))
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%disp('Parseval is right!');
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else
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disp('Parseval theorem is not right...');
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end
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end
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if fsamp <= 1e+100
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%Frequency Axis
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freq_vec = linspace(-fsamp/2,fsamp/2,length(psd));
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freq_vec = reshape(freq_vec,size(psd_plot));
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if ~isempty(options.displayname)
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plot(freq_vec*1e-9,psd_plot,'Linewidth',0.5,'DisplayName',options.displayname,'Parent',ax);
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else
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plot(freq_vec*1e-9,psd_plot,'Linewidth',0.5,'Parent',ax);
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end
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xlabel('Frequency [GHz]')
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else
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%Wavelength Axis
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freq_vec = physconst('LightSpeed')*linspace(-fsamp/2,fsamp/2,length(psd))./((physconst('LightSpeed')/1550e-9)^2);
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if ~isempty(options.displayname)
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plot(freq_vec*1e9,psd_plot,'Linewidth',0.5,'DisplayName',options.displayname,'Parent',ax);
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else
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plot(freq_vec*1e9,psd_plot,'Linewidth',0.5,'Parent',ax);
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end
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xlabel('Wavelength [nm]')
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end
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ylabel('Magnitude [dB]')
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legend
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grid minor;
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end
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%%
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function obj = normalize(obj,options)
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arguments
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obj Signal
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options.mode normalization_mode = normalization_mode.rms
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end
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switch options.mode
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case normalization_mode.rms
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obj.signal = obj.signal/sqrt(mean(abs(obj.signal).^2,"all"));
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case normalization_mode.oneone
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obj.signal = obj.signal/max(abs(obj.signal));
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end
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end
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%%
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function obj = delay(obj,options)
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arguments
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obj Opticalsignal
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options.delay_meter double = 0
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end
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delay_t = options.delay_meter /(physconst("LightSpeed")/1.4677);
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delay_n = round(delay_t .* obj.fs);
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% build "long" hann window to fade the signal in and out
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% -> prevent hard step in the signal!
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hann_wind = hann(200);
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ones_wind = ones(size(obj.signal));
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ones_wind(1:100) = hann_wind(1:100);
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ones_wind(end-100:end) = hann_wind(end-100:end);
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% subtract average
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mu = mean(obj.signal,"all");
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obj.signal = obj.signal - mu;
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%apply hann
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obj.signal = obj.signal .* ones_wind;
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%add average again
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obj.signal = obj.signal + mu;
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% finally circshift the signal
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obj.signal=circshift(obj.signal,delay_n);
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end
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end
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end
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