210 lines
7.2 KiB
Matlab
210 lines
7.2 KiB
Matlab
% minimal example IM/DD
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M = 4;
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fsym = 160e9;
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apply_pulsef = 1;
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fdac = 256e9;
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fadc = 256e9;
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random_key = 1;
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rcalpha = 0.05;
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kover = 16;
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duob_mode = db_mode.no_db;
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vbias_rel = 0.5;
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u_pi = 3;
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vbias = -vbias_rel*u_pi;
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laser_wavelength = 1293;
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laser_linewidth = 0;
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tx_bw_nyquist = 0.8;
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% Channel
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link_length = 1;
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% RX
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rop = -9;
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rx_bw_nyquist = 0.8;
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vnle_order1 = 50;
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vnle_order2 = 7;
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vnle_order3 = 7;
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vnle_order=[vnle_order1,vnle_order2,vnle_order3];
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dfe_order = [0 0 0];
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pf_ncoeffs = 1;
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alpha = 0;
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len_tr = 4096*2;
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mu_ffe1 = 0.0001;
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mu_ffe2 = 0.0008;
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mu_ffe3 = 0.001;
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mu_dc = 0.005;
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% mu_dc = 0;
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mu_ffe = [mu_ffe1 mu_ffe3 mu_ffe3];
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mu_dfe = 0.0004;
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sf = signalform.prms;
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Tx_bits = Signalgenerator( ...
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"form", sf, ...
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"M", M, ...
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"order", 16).process();
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Symbols = PAMmapper(M,0).map(Tx_bits);
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Symbols.fs = fsym;
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Symbols_plain = Symbols;
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pr = Partialresponse("order", 1,"M",M);
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Symbols = pr.precode(Symbols);
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pform = Pulseformer("fsym",fsym,"fdac",4*fsym,"pulse","rc","pulselength",16,"alpha",rcalpha);
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Digi_sig = pform.process(Symbols);
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n = 10;
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Digi_sig = Digi_sig.resample("fs_in",Digi_sig.fs,"fs_out",fdac,"n",n,"beta",5);
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%%%%% AWG
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El_sig = M8199A("kover",kover).process(Digi_sig);
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% El_sig = AWG("fdac",fdac,"f_cutoff",fsym*0.4,"lpf_active",1,"kover",kover,"bit_resolution",12,"upsampling_method","samplehold","precomp_sinc_rolloff",1).process(Digi_sig);
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tx_bwl = fsym*0.3;
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El_sig = Filter('filtdegree',4,"f_cutoff",tx_bwl,"fs",fdac*kover,"filterType",filtertypes.butterworth,"active",true).process(El_sig);
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El_sig.spectrum("displayname",'Digi Spectrum','fignum',1,'normalizeTo0dB',1);
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xlim([0,130]);
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ylim([-30,5]);
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% El_sig = El_sig.setPower(0,"dBm");
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%%%%% Electrical Driver Amplifier %%%%%%
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% El_sig = Amplifier("amp_mode","ideal_no_noise","gain_mode","gain","amplification_db",3).process(El_sig);
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El_sig = El_sig.normalize("mode","oneone");
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scaling = 0.8*(u_pi/2-abs(vbias-u_pi/2));
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El_sig = El_sig .* scaling;
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%%%%% MODULATE E/O CONVERSION %%%%%%
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[Opt_sig] = EML("mode",eml_mode.im_cosinus,"power",3,"fsimu",El_sig.fs,"lambda",laser_wavelength,"bias",vbias,"u_pi",u_pi,"linewidth",laser_linewidth,"randomkey",random_key+1,"alpha",alpha).process(El_sig);
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Opt_sig.spectrum("displayname",'Opt Spectrum','fignum',10,'normalizeTo0dB',1);
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% Opt_sig.eye(fsym,M,"displayname",'eye adter modulator','fignum',2026);
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Opt_sig = Fiber("fsimu",Opt_sig.fs,"fiber_length",link_length,"alpha",0.3,"D",0,"lambda0",1310,"gamma",0,"Dslope",0.07).process(Opt_sig);
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%%%%%% ROP %%%%%%
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Rx_sig = Amplifier("amp_mode","ideal_no_noise","gain_mode","output_power","amplification_db",rop).process(Opt_sig);
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%%%%%% PD Square Law %%%%%%
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Rx_sig = Photodiode("fsimu",fdac*kover,"dark_current",2e-08,"responsivity",1,"temperature",20,"nep",1.8e-11).process(Rx_sig);
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%%%%%% Low-pass RX (PD, El. Connectors and Scope %%%%%%
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rx_bwl = 80e9;
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Rx_sig = Filter('filtdegree',4,"f_cutoff",rx_bwl,"fs",fdac*kover,"filterType",filtertypes.butterworth,"active",true).process(Rx_sig);
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% %%%%%% Low-pass Scope %%%%%%
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Lp_scpe = Filter('filtdegree',4,"f_cutoff",110e9,"fs",fadc,"filterType",filtertypes.butterworth,"active",true);
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%%%%%% Scope %%%%%%
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Scpe_sig = Scope("fsimu",fdac*kover,"fadc",fadc,...
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"delay",0,"fixed_delay",0,"filtertype",filtertypes.butterworth,...
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"samplingdelay",0,"rand_samplingdelay",0,"freq_offset",0,"samp_jitter",0,...
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"adcresolution",8,"quantbuffer",0.1,'block_dc',1,'lpf_active',1,'H_lpf',Lp_scpe).process(Rx_sig);
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%%
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% 1) matched filter
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% pulse is symmetric, hence we can use pulsef firectly as matched filter.
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% It feels off (bit I think correct) that the fsym is now the output freq.!!
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% -> output 2 sps to omit timing recovery!?
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if 0
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Pform = Pulseformer("fsym",fsym,"fdac",2*fsym,"pulse","rrc","pulselength",16,"alpha",rcalpha,"matched",1);
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Scpe_sig = Pform.process(Scpe_sig);
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end
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% Scpe_sig.spectrum("displayname",'Signal after matched filter','fignum',1,'normalizeTo0dB',1);
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%
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% %%
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% %%%%%% Sample to 2x fsym %%%%%%
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Scpe_sig = Scpe_sig.resample("fs_out",2*fsym);
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Scpe_sig.signal = Scpe_sig.signal(1:2*length(Symbols));
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%%
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%%%%%% Sync Rx signal with reference %%%%%%
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[Scpe_sig,~] = Scpe_sig.tsynch("reference",Symbols,"fs_ref",fsym,"debug_plots",0);
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% Scpe_sig.spectrum("displayname",'Opt Spectrum','fignum',11,'normalizeTo0dB',1);
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% Scpe_sig = Filter('filtdegree',4,"f_cutoff",Symbols.fs.*0.5,"fs",Scpe_sig.fs,"filterType",filtertypes.gaussian,"active",true).process(Scpe_sig);
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Scpe_sig = Scpe_sig - mean(Scpe_sig.signal);
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Scpe_sig.signal = Scpe_sig.signal(1:2*length(Symbols));
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%% -------------------- MLSE --------------------
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mlse_ = MLSE("DIR",[1,1],"duobinary_output",0,"M",M,'trellis_states',PAMmapper(M,0).levels);
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ffe_order = [50, 2, 2];
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eq_ = EQ("Ne",ffe_order,"Nb",[0,0,0],"training_length",len_tr,"training_loops",5,"dd_loops",5, ...
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"K",2,"DCmu",mu_dc,"DDmu",[mu_ffe mu_dfe],"DFEmu",0.005,"FFEmu",0,"plotfinal",0,"ideal_dfe",1);
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%Duobinary Targeting
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db_ref_sequence = Duobinary().encode(Symbols);
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[eq_signal, eq_noise] = eq_.process(Scpe_sig,db_ref_sequence);
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showLevelHistogram(eq_signal,db_ref_sequence)
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[mlse_sig_sd,LLR,GMI_MLSE] = mlse_.process(eq_signal,Symbols);
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Rx_bits = PAMmapper(M,0).demap(mlse_sig_sd);
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Tx_bits_omitprecode = PAMmapper(M,0).demap(Symbols);
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[bits,errors,ber_wo,errorIndice] = calc_ber(Rx_bits.signal,Tx_bits_omitprecode.signal);
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fprintf(["BER w/o precode: %.2d \n"],ber_wo);
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showErrorBurstCount(mlse_sig_sd, Symbols,"displayname",'MLSE DB w/o Precode','fignum',4); % prior to coding
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%%
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mlse_sig_sd = pr.encode(mlse_sig_sd);
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mlse_sig_sd = pr.decode(mlse_sig_sd);
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Rx_bits = PAMmapper(M,0).demap(mlse_sig_sd);
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[bits,errors,ber,errorIndice] = calc_ber(Rx_bits.signal,Tx_bits.signal);
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fprintf(["BER w/ precode: %.2d \n"],ber);
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showErrorBurstCount(mlse_sig_sd, Symbols_plain,"displayname",'MLSE DB w/ Precode','fignum',5);
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%% -------------------- FFE --------------------
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ffe_order = [50, 0, 0];
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eq_ = EQ("Ne",ffe_order,"Nb",[2,0,0], ...
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"training_length",len_tr,"training_loops",5,"dd_loops",5, ...
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"K",2,"DCmu",mu_dc,"DDmu",[mu_ffe mu_dfe],"DFEmu",0.005, ...
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"FFEmu",0,"plotfinal",0,"ideal_dfe",0);
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% eq_ = FFE("epochs_tr",4,"epochs_dd",5,"len_tr",4096,"mu_dd",0.01,"mu_tr",0.01,"order",50,"sps",2,"decide",0, "adaption",adaption_method.nlms,"dd_mode",1);
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% eq_ = FFE_DFE("epochs_tr",5,"epochs_dd",5,"len_tr",512,"ffe_mu_dd",1e-4,"dfe_mu_dd",5e-4,"ffe_mu_tr",0,"dfe_mu_tr",0,"ffe_order",99,"dfe_order",99,"sps",2,"decide",0);
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[eq_signal_sd, eq_noise] = eq_.process(Scpe_sig, Symbols);
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eq_signal_hd = PAMmapper(M,0).quantize(eq_signal_sd);
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Rx_bits = PAMmapper(M,0).demap(eq_signal_hd);
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Tx_bits_omitprecode = PAMmapper(M,0).demap(Symbols);
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[bits,errors,ber_wo,errorIndice] = calc_ber(Rx_bits.signal,Tx_bits_omitprecode.signal);
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fprintf(["BER w/o precode: %.2d \n"],ber_wo);
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showErrorBurstCount(eq_signal_hd, Symbols,"displayname",'No Precode','fignum',8); % prior to coding
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eq_signal_hd = pr.encode(eq_signal_hd);
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eq_signal_hd = pr.decode(eq_signal_hd);
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Rx_bits = PAMmapper(M,0).demap(eq_signal_hd);
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[bits,errors,ber,errorIndice] = calc_ber(Rx_bits.signal,Tx_bits.signal);
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fprintf(["BER w/ precode: %.2d \n"],ber);
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showErrorBurstCount(eq_signal_hd, Symbols_plain,"displayname",'Incl. Precode','fignum',7);
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