Update April
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Silas Oettinghaus
227
projects/IMDD_base_system/imddmodel.m
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227
projects/IMDD_base_system/imddmodel.m
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function output = imddmodel(sir,dcmode)
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for realiz = 1:3
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rng(realiz);
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%% Set Simulation Variables
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delay = 0;10+(10*realiz); %mpi delay in meter
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fiblen = 0; %main link in km
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laser_linewidth =0e6;
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O = 18; %order of prbs
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N = 2^(O-1); %length of prbs
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[~,seed] = prbs(O,1); %initialize first seed of prbs
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% Modulation
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M = 4; %PAM-M
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bitpattern = zeros(N,log2(M));
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% Symbol Rate
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fsym = 112e9;
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% DAC Rate
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fdac = 120e9;
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% Simulation oversampling rate "k";
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kover = 16;
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% ADC Rate
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fadc = 256e9;
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% Simulation frequency in "analog domain"
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fsimu = kover * fdac ;
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%% B) CONSTRUCT ALL CLASSES %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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digimod = PAMmapper(M,0);
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pulseform = Pulseformer("pulseform","rrc","fdac",fdac,"fsym",fsym,"pulselength",32,"rrcalpha",0.027);
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awg = AWG('fdac',fdac,'kover',kover,'lpf_active',1,'f_cutoff',56e9,'lpf_type',filtertypes.gaussian,'bit_resolution',5.5);
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lp_laser = Filter('filtdegree',1,"f_cutoff",50e9,"fsamp",fdac*kover,"filterType",filtertypes.bessel_inp);
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u_pi = 3.5;
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vbias = (0.5*u_pi)-u_pi;
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extmodlaser = EML("mode",eml_mode.im_cosinus,"power",5,"fsimu",fsimu,"lambda",1550,"bias",vbias,"u_pi",u_pi,"linewidth",laser_linewidth);
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fib = Fiber("fsimu",fdac*kover,"fiber_length",fiblen,"alpha",0.2,"D",16,"lambda0",thz2nm(193.1),"gamma",0);
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reflectionpoint = Amplifier("amp_mode","ideal_no_noise","gain_mode","gain","amplification_db",sir);
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reflectionprop = Fiber("fsimu",fdac*kover,"fiber_length",delay/1000,"alpha",0.2,"D",16,"lambda0",1550,"gamma",0);
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opticatten = Amplifier("amp_mode","ideal_no_noise","gain_mode","output_power","amplification_db",-8);
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phdiode = Photodiode("fsimu",fdac*kover,"dark_current",2e-08,"responsivity",1,"temperature",20);
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lp_diode = Filter('filtdegree',1,"f_cutoff",50e9,"fsamp",fdac*kover,"filterType",filtertypes.bessel_inp);
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scp = Scope("fsimu",fdac*kover,"fadc",fadc,...
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"delay",0,"fixed_delay",0,"lpf_bw",113e9,"filtertype",filtertypes.butterworth,...
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"samplingdelay",0,"rand_samplingdelay",0,"freq_offset",0,"samp_jitter",0,...
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"adcresolution",6,"quantbuffer",0.1,'block_dc',1);
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eq = EQ("K",2,"plottrain",0,"plotfinal",0,...
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"training_length",4096,"training_loops",2,...
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"Ne",[50,5,3],"Nb",[3,2,2],...
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"DCmu",0.05,"DDmu",[0.0004 0.0005 0.0006 0.0007 ],"DFEmu",0.005,"FFEmu",0.005,...
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"dd_loops",2,"epsilon",[10 100 1000 ],"M",2,...
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"thres",[0.005 0.004 0.0005 ],"l1act",0,"delay",0,"rho",0.0005,"ideal_dfe",0,"DB_aim",0);
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eq2 = EQ_silas("Ne",[20,0,0],"Nb",[3,0,0],"trainlength",4096,"mu_dc_dd",0.005,"mu_dc_train",0.05,...
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"mu_ffe_train",0.005,"mu_combined_dd",[0.0004 0.0006 0.0003 0.005],"ddloops",3,"dcmode",dcmode);
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%% C) PROCESS TX %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% 1) PRBS Generation
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for i = 1:log2(M)
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[bitpattern(:,i),seed] = prbs(O,N,seed);
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end
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% 2 ) Build Inf. signal class
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bits = Informationsignal(bitpattern);
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% 3) Digi modulation -> PAM-M signal
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digimod_out = digimod.map(bits);
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% 4) Pulse shaping -> racos
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X = pulseform.process(digimod_out);
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% 5) AWG (lowpass, quantization, sample and hold)
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X = awg.process(X);
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% 6) Lowpass behavior of laser and hf-cable? why twice?
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X = lp_laser.process(X);
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X = lp_laser.process(X);
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% 7) Normalize signal
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X = X.normalize("mode","oneone");
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X.signal = X.signal .* 1.3800;
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%% D) PROCESS OPTICAL CHANNEL %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% 1) Laser; Modulation -> OPTICAL DOMAIN
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[X,extmodlaser] = extmodlaser.process(X);
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% 2) Main fiber propagation
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X = fib.process(X);
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if delay ~= 0
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% 3) Reflection
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% Reflection is just an attenuation
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R = reflectionpoint.process(X);
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% Propagate back and forth (actual fiber propagation)
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R = reflectionprop.process(R);
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% Delay the reflected signal
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[R,n] = R.delay("delay_meter",delay);
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% Add together
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X.signal = X.signal(n:end);
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R.signal = R.signal(n:end);
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%disp(['SIR ',num2str(10*log10(X.power/R.power))]);
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X = X+R;
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% 4) Equalize
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% cut reference signal to correct length (nessecary due to MPI delay)
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digimod_out.signal = digimod_out.signal(round(n * fsym/fsimu) : end,:);
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bitpattern = bitpattern(round(n * fsym/fsimu):end,:);
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end
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% 4) Attenuation
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X = opticatten.process(X);
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% X = edfaamp.process(X);
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% 5) Photo Diode -> ELECTRICAL DOMAIN
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X = phdiode.process(X);
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X = lp_diode.process(X);
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%% E) PROCESS RX %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% 1) Oscilloscope (Sampling to f_adc; Quantization; Bandwidth Limitation)
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X = scp.process(X);
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% 2) Resample to 2x symbol rate
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X = X.resample("fs_out",2*fsym,"fs_in",fadc);
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% 3) Normalize
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Eq_in = X.normalize("mode","rms");
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% MPI reduction DC removal BEFORE EQ
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wl = 3000; % symbols
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Eq_in.signal = Eq_in.signal - 1/wl .* movsum( Eq_in.signal,[wl/2,wl/2]);
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% Equalize Signal
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[Eq_out] = eq2.process(Eq_in,digimod_out);
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%% A1: MPI reduction DC removal
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wl = 1000; % symbols
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yk_dcsm = Eq_out;
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yk_dcsm.signal = Eq_out.signal - 1/wl .* movsum( Eq_out.signal,[wl/2,wl/2]);
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%% A2: MPI reduction Level wise error removal
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yk_lvsm = Eq_out;
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yk_lvlp = Eq_out;
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pre_decision_level_uni = digimod.decide_pamlevel(Eq_out);
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pre_decision_level_bi = ( pre_decision_level_uni*2-3 ) .* 1/sqrt(5);
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e = Eq_out.signal - pre_decision_level_bi;
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lp_mpi = Filter('filtdegree',1,"f_cutoff",2e6,"fsamp",fsym,"filterType",filtertypes.bessel_inp);
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filtered = lp_mpi.process(e);
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wl = 30; % symbols
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smoothed = ( 1/wl .* movsum(e,[wl/2,wl/2]) );
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% remove interference
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for level = 0:3
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yk_lvsm.signal(pre_decision_level_uni==level) = yk_lvsm.signal(pre_decision_level_uni==level) - smoothed(pre_decision_level_uni==level);
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yk_lvlp.signal(pre_decision_level_uni==level) = yk_lvlp.signal(pre_decision_level_uni==level) - filtered(pre_decision_level_uni==level);
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end
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%% PROCESS RX %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% 1) Digi Demod
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d_bm = digimod.demap(Eq_out);
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d_dcsm = digimod.demap(yk_dcsm);
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d_lvsm = digimod.demap(yk_lvsm);
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d_lvlp = digimod.demap(yk_lvlp);
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% 2) BER
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dbit = length(d_bm.signal)-length(bitpattern);
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[~,errors_bm,ber_bm(realiz),loc] = calc_ber(d_bm.signal(1:end-dbit,:) ,bitpattern(1:end,:),"skip",0,"returnErrorLocation",1);
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[~,errors_dcsm,ber_dcsm(realiz)] = calc_ber(d_dcsm.signal(1:end-dbit,:) ,bitpattern(1:end,:),"skip",0,"returnErrorLocation",0);
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[~,errors_lvsm,ber_lvsm(realiz)] = calc_ber(d_lvsm.signal(1:end-dbit,:) ,bitpattern(1:end,:),"skip",0,"returnErrorLocation",0);
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[~,errors_lvlp,ber_lvlp(realiz)] = calc_ber(d_lvlp.signal(1:end-dbit,:) ,bitpattern(1:end,:),"skip",0,"returnErrorLocation",0);
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end
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output.ber_bm = mean(ber_bm);
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output.ber_dcsm = mean(ber_dcsm);
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output.ber_lvsm = mean(ber_lvsm);
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output.ber_lvlp = mean(ber_lvlp);
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end
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