220 lines
9.3 KiB
Matlab
220 lines
9.3 KiB
Matlab
function [ber] = imdd_example(varargin)
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% BASIC IMDD Model...
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% varargin is either empty or a struct, i.e.:
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%
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curFolder = pwd;
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funcFolder=fileparts(mfilename('fullpath'));
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if ~isempty(funcFolder)
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cd(funcFolder);
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end
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% TX
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M = 4;
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fsym = 180e9;
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f_nyquist = fsym/2;
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apply_pulsef = 0;
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fdac = 2*fsym;%256e9;
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fadc = 2*fsym;%256e9;
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fdac = 256e9;
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fadc = 256e9;
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random_key = 1;
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db_precode = 0;
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emulate_precode = 0;
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discard_precode = 0;
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db_encode = 0;
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% duob_mode = db_mode.db_emulate;
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emulate_db = 1;
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rcalpha = 0.05;
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kover = 16;
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vbias_rel = 0.5;
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u_pi = 2.9;
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vbias = -vbias_rel*u_pi;
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laser_wavelength = 1310;
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laser_linewidth = 0;
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tx_bw_nyquist = 1.5;
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% Channel
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link_length = 1;
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% RX
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rop = -8;
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rx_bw_nyquist = 0.7;
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% EQ
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eq_mode = equalizer_structure.vnle_pf_mlse;
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ffe_order=[50,0,0];
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vnle_order=[50,7,7];
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dfe_order = [2 0 0];
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len_tr = 4096*2;
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mu_ffe = [0.0004 0.0004 0.0004];
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mu_dfe = 0.0004;
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mu_dc = 0.00;
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dfe_ = sum(dfe_order)>0;
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% Parse optional input arguments
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if ~isempty(varargin)
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var_s = varargin{1};
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if isstruct(var_s)
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fields = fieldnames(var_s);
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for i = 1:numel(fields)
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eval([fields{i}, ' = ', num2str( var_s.(fields{i}) ), ';']);
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fprintf("%s <-- %.2f \n", fields{i}, var_s.(fields{i}));
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end
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else
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error('Optional variables should be passed as a struct.');
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end
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end
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%%%% TX Signal
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Pform = Pulseformer("fsym",fsym,"fdac",4*fsym,"pulse","rrc","pulselength",16,"rrcalpha",rcalpha);
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[Digi_sig,Symbols,Bits] = PAMsource(...
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"fsym",fsym,"M",M,"order",19,"useprbs",1,...
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"fs_out",fdac,...
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"applyclipping",0,"clipfactor",1.5,...
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"applypulseform",apply_pulsef,"pulseformer",Pform,...
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"randkey",random_key,...
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"db_precode",db_precode,"db_encode",db_encode,...
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"mrds_code",0,"mrds_blocklength",512).process();
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Digi_sig.spectrum("displayname",'Digi Spectrum','fignum',10,'normalizeTo0dB',1);
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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,"lpf_active",0,"kover",kover,"bit_resolution",12,"upsampling_method","samplehold","precomp_sinc_rolloff",1).process(Digi_sig);
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% El_sig.spectrum("displayname",'Digi Spectrum','fignum',100,'normalizeTo0dB',0);
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% El_sig = El_sig.setPower(0,"dBm");
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%%%%% Low-pass el. components %%%%%%
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El_sig = Filter('filtdegree',4,"f_cutoff",tx_bw_nyquist.*f_nyquist,"fs",fdac*kover,"filterType",filtertypes.butterworth,"active",true).process(El_sig);
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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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%%%%% 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).process(El_sig);
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%%%%%% Fiber %%%%%%
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Opt_sig = Fiber("fsimu",Opt_sig.fs,"fiber_length",link_length/1000,"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_sig = Filter('filtdegree',4,"f_cutoff",rx_bw_nyquist.*f_nyquist,"fs",fdac*kover,"filterType",filtertypes.butterworth,"active",true).process(Rx_sig);
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% %%%%%% Low-pass Scope %%%%%%
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%dactivated in scope module!
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Lp_scpe = Filter('filtdegree',4,"f_cutoff",10e9,"fs",fadc,"filterType",filtertypes.butterworth,"active",true);
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% Rx_sig.spectrum("displayname",'Analog Rx Spectrum','fignum',100,'normalizeTo0dB',1);
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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',0,'H_lpf',Lp_scpe).process(Rx_sig);
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% Scpe_sig.spectrum("displayname",'Digital (256 GSa/s) Rx Spectrum','fignum',100,'normalizeTo0dB',1);
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%%%%%% Sample to 2x fsym %%%%%%
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Scpe_sig = Scpe_sig.resample("fs_in",fadc,"fs_out",2*fsym);
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%%%%%% Sync Rx signal with reference %%%%%%
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[Scpe_sig,S] = Scpe_sig.tsynch("reference",Symbols,"fs_ref",fsym);
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Scpe_sig.spectrum("displayname",'Prior DSP (2x fsym) Spectrum','fignum',100,'normalizeTo0dB',1);
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%%% EQUALIZING
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ber = struct();
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switch eq_mode
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case equalizer_structure.ffe
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%FFE
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if db_precode
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Bits_ = PAMmapper(M,0).demap(Symbols);
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else
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Bits_ = Bits;
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end
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eq_ffe = EQ("Ne",ffe_order,"Nb",dfe_order,"training_length",len_tr,"training_loops",5,"dd_loops",5,"K",2,"DCmu",mu_dc,"DDmu",[mu_ffe mu_dfe],"DFEmu",0.005,"FFEmu",0,"plotfinal",0,"ideal_dfe",1);
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% eq_ffe = FFE("epochs_tr",5,"epochs_dd",5,"len_tr",len_tr,"mu_dd",mu_ffe(1),"mu_tr",0,"order",ffe_order(1),"sps",2,"decide",0);
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% eq_ffe = FFE_DCremoval("epochs_tr",5,"epochs_dd",5,"len_tr",len_tr,"mu_dd",mu_ffe(1),"mu_tr",0,"order",ffe_order(1),"sps",2,"decide",0,"dc_buffer_len",512,"mu_dc",0.05);
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[eq_sig,eq_noise,ber.ber_ffe,totalErrors] = vnle( eq_ffe,M,Scpe_sig ,Symbols, Bits_);
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eq_noise.spectrum("displayname",'Noise Spectrum after FFE','fignum',41,'normalizeTo0dB',0);
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case equalizer_structure.vnle
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if db_precode
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Bits_ = PAMmapper(M,0).demap(Symbols);
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else
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Bits_ = Bits;
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end
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%VNLE
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eq_vnle = EQ("Ne",vnle_order,"Nb",dfe_order,"training_length",len_tr,"training_loops",5,"dd_loops",5,"K",2,"DCmu",mu_dc,"DDmu",[mu_ffe mu_dfe],"DFEmu",0.005,"FFEmu",0,"plotfinal",0,"ideal_dfe",1);
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[eq_sig,eq_noise,ber.ber_vnle,totalErrors] = vnle(eq_vnle,M,Scpe_sig ,Symbols, Bits_);
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eq_noise.spectrum("displayname",'Noise Spectrum after VNLE','fignum',41,'normalizeTo0dB',0);
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case equalizer_structure.vnle_pf_mlse
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if db_precode
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Bits_ = PAMmapper(M,0).demap(Symbols);
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else
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Bits_ = Bits;
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end
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%VNLE + PF + MLSE
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eq_mlse = EQ("Ne",vnle_order,"Nb",dfe_order,"training_length",len_tr,"training_loops",5,"dd_loops",5,"K",2,"DCmu",mu_dc,"DDmu",[mu_ffe mu_dfe],"DFEmu",0.005,"FFEmu",0,"plotfinal",0,"ideal_dfe",1);
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eq_mlse = FFE_DCremoval("epochs_tr",5,"epochs_dd",5,"len_tr",len_tr,"mu_dd",mu_ffe(1),"mu_tr",0,"order",ffe_order(1),"sps",2,"decide",0,"dc_buffer_len",512,"mu_dc",0.05);
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eq_mlse = FFE("epochs_tr",5,"epochs_dd",5,"len_tr",len_tr,"mu_dd",mu_ffe(1),"mu_tr",0,"order",ffe_order(1),"sps",2,"decide",0);
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pf_ = Postfilter("ncoeff",1);
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mlse_ = MLSE("DIR",[0,0],"duobinary_output",0,"M",[],"trellis_states",[]);
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[eq_sig,eq_noise,ber.ber_mlse,totalErrors] = vnle_postfilter_mlse(eq_mlse , pf_, mlse_,M, Scpe_sig ,Symbols, Bits_);
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pf_.showFilter(eq_noise);
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eq_noise.spectrum("displayname",'Noise Spectrum after VNLE+PF','fignum',41,'normalizeTo0dB',0);
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case equalizer_structure.db_precoded
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%EQ targets DB => less precompensation; pre-coded
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mlse_db_pre = MLSE("DIR",[1,1],"duobinary_output",1,"M",M,"trellis_states",PAMmapper(M,0).levels);
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eq_db_pre = EQ("Ne",vnle_order,"Nb",dfe_order,"training_length",len_tr,"training_loops",5,"dd_loops",5,"K",2,"DCmu",mu_dc,"DDmu",[mu_ffe mu_dfe],"DFEmu",0.005,"FFEmu",0,"plotfinal",0,"ideal_dfe",1);
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[eq_sig,eq_noise,ber.ber_db,totalErrors] = duobinary_target(eq_db_pre, mlse_db_pre,M, Scpe_sig ,Symbols, Bits);
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eq_noise.spectrum("displayname",'Noise Spectrum after DB','fignum',41,'normalizeTo0dB',0);
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%->append BER to DB
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case equalizer_structure.db_encoded
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%db signaling => db encoded
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mlse_db_enc = MLSE("DIR",[1,1],"duobinary_output",1,"M",M,"trellis_states",PAMmapper(M,0).levels);
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eq_db_enc = EQ("Ne",vnle_order,"Nb",dfe_order,"training_length",len_tr,"training_loops",5,"dd_loops",5,"K",2,"DCmu",mu_dc,"DDmu",[mu_ffe mu_dfe],"DFEmu",0.005,"FFEmu",0,"plotfinal",0,"ideal_dfe",1);
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[eq_sig,eq_noise,ber.ber_db_enc,totalErrors] = duobinary_signaling(eq_db_enc, mlse_db_enc,M, Scpe_sig ,Symbols, Bits);
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%->append BER to DB
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end
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% fprintf('BER FFE: %.2e \n',ber.ber_mlse);
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% % El_sig.spectrum("displayname",'Tx Spectrum','fignum',10,'normalizeTo0dB',1);
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% Scpe_sig.spectrum("displayname",'Rx Spectrum','fignum',100,'normalizeTo0dB',1);
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if ~isempty(curFolder)
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cd(curFolder);
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end
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end |