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start implementation of class based simulation of a IM/DD communication system. Mostly based on Move-It but cleaned up and with focus on direct detection, however I try to keep the versatility of move-it alive.
2023-05-12 15:28:23 +02:00
parent 69df41340f
commit 6d53823466
109 changed files with 1824 additions and 0 deletions
--- a/Classes/Filter.m
+++ b/Classes/Filter.m
@@ -0,0 +1,139 @@
+classdef Filter
+    %FILTER Summary of this class goes here
+    %   Detailed explanation goes here
+
+    properties
+        H
+        filterType
+        f_cutoff
+
+
+        signal_length
+        filtdegree
+        passband_ripple 
+        stopband_ripple
+        fdac
+    end
+
+    methods
+        function obj = Filter(options)
+            %FILTER Construct an instance of this class
+            %   Detailed explanation goes here
+            arguments
+                options.filterType = 1;
+                options.f_cutoff   = 0;
+                options.fdac       = 0;
+                options.filtdegree = 3;
+                options.passband_ripple = 0.5;
+                options.stopband_ripple = 0.5;
+            end
+            
+
+            obj.filterType = options.filterType;
+
+
+            obj.f_cutoff        = options.f_cutoff;
+            obj.filtdegree      = options.filtdegree;
+            obj.passband_ripple = options.passband_ripple;
+            obj.stopband_ripple = options.stopband_ripple;
+            obj.fdac            = options.fdac;
+
+        end
+
+        function yout = process(obj,xin)
+
+            obj.signal_length = length(xin);
+
+            obj.H = obj.buildFilter(obj.filterType);
+
+            yout = obj.applyFilter(xin);
+
+        end
+
+        function y_filtered = applyFilter(obj,xin)
+
+            y_filtered = ifft(obj.H.*fft(xin));
+
+        end
+
+        function H = buildFilter(obj,filterType)
+
+            rp = obj.passband_ripple; %passband ripple
+            rs = obj.stopband_ripple; %stopband ripple
+
+            switch filterType
+                case 1
+
+                    % Bessel filter, impulse invariant transformed
+
+                    [B, A] = besself(obj.filtdegree, 2*pi*obj.f_cutoff);
+                    [B ,A] = impinvar(B,A,obj.fdac);
+
+                case 2
+
+                    % Bessel filter, impulse bilinear transformed
+
+                    [Z, P, K] = besself(obj.filtdegree, 2*pi*obj.f_cutoff);
+                    [Z ,P, K] = bilinear(Z,P,K,obj.fdac);
+                    [B ,A] = zp2tf(Z ,P ,K);
+
+                case 3
+
+                    % Butterworth filter
+                    if obj.lowpass == 1 %lowpass
+                        [B, A] = butter(obj.filtdegree, obj.f_cutoff/(obj.fdac/2),'low');
+                    else % highpass
+                        [B, A] = butter(obj.filtdegree, obj.f_cutoff/(obj.fdac/2),'high');
+                    end
+
+                case 4
+
+                    % Chebyshev 1 filter
+
+                    [B, A] = cheby1(obj.filtdegree,rp, obj.f_cutoff/(obj.fdac/2));
+
+                case 5
+
+                    % Chebyshev 2 filter
+
+                    [B, A] = cheby2(obj.filtdegree,rs, obj.f_cutoff/(obj.fdac/2));
+
+                case 6
+
+                    % Elliptic filter
+
+                    [B, A] = ellip(obj.filtdegree,rp,rs,obj.f_cutoff/(obj.fdac/2));
+
+                case 7
+
+                    % Hamming filter
+
+                    g=(obj.filtdegree-1)/2;
+                    wc=obj.f_cutoff/(obj.fdac/2);
+                    B = wc*sinc(wc*(-g:g)).*hamming(obj.filtdegree)';
+                    A=1;
+
+                case 8
+
+                    % Raised Cosine filter
+
+                    B = firrcos(obj.filtdegree,obj.f_cutoff,para.df,obj.fdac);
+                    A=1;
+
+                case 9
+
+                    % Sinc filter
+
+                    g=(obj.filtdegree-1)/2;
+                    wc=obj.f_cutoff/(obj.fdac/2);
+                    B = wc*sinc(wc*(-g:g));
+                    A=1;
+
+            end
+
+            H = freqz(B, A, obj.signal_length,'whole');
+
+        end
+    end
+end
+