162 lines
4.0 KiB
Matlab
162 lines
4.0 KiB
Matlab
clear all
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O = 15; %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 = 56e9;
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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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%CONSTRUCTION
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pam_mapper = PAMmapper(M,0);
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awg = AWG('preset','M8196A','fdac',fdac,'kover',kover,'lpf_active',0,'f_cutoff',80e9,'lpf_type',filtertypes.bessel_bilin);
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%fil_tx = Filter('filtdegree',1,"f_cutoff",80e9,"fsamp",fdac,"filterType",filtertypes.bessel_bilin);
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fil_tx = Filter('filtdegree',1,"f_cutoff",50e9,"fsamp",fdac,"filterType",filtertypes.bessel_bilin);
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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",emlmodes.im_cosinus,"power",10,"fsimu",fsimu,"lambda",1550,"bias",vbias,"u_pi",u_pi,"linewidth",1000);
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amp = Amplifier("amplification_db",10,"amp_mode","gain","type","ideal","saturation_mode",0,'saturation_power',10);
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fib = Fiber("fsimu",fdac*kover,"fiber_length",2,"alpha",0.2,"D",17,"lambda0",1550);
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phdiode = Photodiode("fsimu",fdac*kover,"dark_current",2e-08,"responsivity",1,"temperature",20);
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fil_diode = Filter('filtdegree',4,"f_cutoff",70e9,"fsamp",fdac,"filterType",filtertypes.bessel_bilin);
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scp = Scope("fsimu",fdac*kover,"fadc",fadc,...
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"delay",0,"fixed_delay",0,"lpf_bw",120e9,"filtertype",filtertypes.bessel_inp,...
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"samplingdelay",0,"rand_samplingdelay",0,"freq_offset",0,"samp_jitter",0,...
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"adcresolution",6,"quantbuffer",0.1);
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eq = EQ("K",2,"plottrain",0,"plotfinal",1,"training_length",2048,"Ne",[25,5,5],"Nb",[2,0,0],"training_loops",5,"DCmu",0.005,"DDmu",[0.0004 0.0004 0.0004 0.0004 ],"DFEmu",0.005,"FFEmu",0,"thres",[0.005 0.004 0.0005 ]);
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%SIMULATE
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% INFORMATION SIGNAL
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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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X = Informationsignal(bitpattern);
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PAMSIG = pam_mapper.map(X);
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X = PAMSIG;
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X.signal = applyPulseShaping(PAMSIG.signal,fsym,fdac);
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% ELECTRICAL DOMAIN
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X = awg.process(X);
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X = fil_tx.process(X);
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% OPTICAL DOMAIN
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X = extmodlaser.process(X);
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X = amp.process(X);
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X = fib.process(X);
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X = phdiode.process(X);
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X = fil_diode.process(X);
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% ELECTRICAL DOMAIN
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X = scp.process(X);
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X = X.resample("fs_out",2*fsym,"fs_in",fadc);
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% INFORMATION SIGNAL
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X = eq.process(X,PAMSIG);
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X = pam_mapper.demap(X);
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% BER
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[bits,errors,BER] = calc_ber(X.signal(:,10000:end-21),bitpattern(10000:end-20,:)',0);
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disp(['BER: ', sprintf('%2E',BER)]);
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disp(X.logbook);
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function yout = applyPulseShaping(xin,fsym,fdac)
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if ~rem(fdac,fsym)
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%ist ein Vielfaches
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sps = fdac / fsym;
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up = sps;
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dn = 1;
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else
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%ist kein Vielfaches
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up = fdac / gcd(fdac, fsym);
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dn = fsym / gcd(fdac, fsym);
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sps= up;
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end
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%Bau das Filter (hier rrc)
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racos_len = 2048;
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alpha = 0.1;
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h = rcosdesign(alpha,racos_len,sps);
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%Apply Filter using Matlab build in fctn.
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yout = upfirdn(xin,h,up,dn);
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%cut signal, which is longer due to fir filter
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st = round(up/dn*racos_len/2); %we need to cut y_out
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en = round(st + (length(xin)*up/dn) -1);
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yout = yout(st:en);
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%Check output integrity
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if round(up/dn * length(xin)) ~= length(yout)
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warning('Check signal length after pulse shaping');
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end
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end
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function [bits,errors,BER] = calc_ber(data_in,data_ref,skip)
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data_ref=logical(data_ref);
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data_in = logical(data_in);
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bits = 0;
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errors=0;
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data_ref_overlap=zeros(size(data_ref,1),skip+(length(data_ref)-size(data_in,2)));
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data_ref_pointer=0;
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% Determine BER
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bits = bits+size(data_in,2)-skip;
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try
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errors = sum( data_in(:,skip+1:end,:) ~= data_ref(:,skip+1:end,:),2 );
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catch
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%warning('BER calculation not optimal: Arrays have incompatible sizes for this operation.')
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errors = NaN;
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end
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try
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errors = sum( data_in(:,skip+1:end,:) ~= data_ref(:,skip+1:end-1,:),2 );
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end
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try
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errors = sum( data_in(:,skip+1:end,:) ~= data_ref(:,skip+1:end-2,:),2 );
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end
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BER = sum(errors)/sum(bits);
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end
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