function [eq_package] = duobinary_target(eq_, mlse_,M, rx_signal, tx_symbols, tx_bits, options)

arguments
    eq_ 
    mlse_ 
    M 
    rx_signal 
    tx_symbols 
    tx_bits 
    options.precode_mode db_mode
    options.showAnalysis = 0;
    options.eth_style_symbol_mapping = 0;
end
    
    %Duobinary Targeting

    [eq_signal, eq_noise] = eq_.process(rx_signal,Duobinary().encode(tx_symbols));

    % dir = [1,1];
    mlse_sig_sd = mlse_.process(eq_signal);

    mlse_sig_hd = PAMmapper(M,0,"eth_style",options.eth_style_symbol_mapping).quantize(mlse_sig_sd);
    
    % precoding to mitigate error propagation, most prominently used in
    % combination with duobinary signaling to avoid catastrophic error
    % behavior (see J.W.M. Bergmans, Digital Baseband Transmission and Recording -> partial response signaling)

    % takes: 
    %   -> eq_signal_hd: hard decision signal after eq
    %   -> tx_symbols: that where used as reference for eq 

    switch options.precode_mode
        case db_mode.db_emulate

        mlse_sig_hd = Duobinary().encode(mlse_sig_hd,"M",M);
        mlse_sig_hd = Duobinary().decode(mlse_sig_hd,"M",M);

        tx_symbols_precoded = Duobinary().encode(tx_symbols);
        tx_symbols_precoded = Duobinary().decode(tx_symbols_precoded);

        tx_bits = PAMmapper(M,0,"eth_style",options.eth_style_symbol_mapping).demap(tx_symbols_precoded);

        case db_mode.db_discard

        % normal dsp for precoded sequence == discard/omit/ignore precode
        tx_bits = PAMmapper(M,0,"eth_style",options.eth_style_symbol_mapping).demap(tx_symbols);

        case db_mode.db_encoded

        % normal DB encoded data (only for 10KM)

        case db_mode.db_precoded

        mlse_sig_hd = Duobinary().encode(mlse_sig_hd,"M",M);
        mlse_sig_hd = Duobinary().decode(mlse_sig_hd,"M",M);

    end

    % M = numel(unique(tx_symbols.signal));
    rx_bits = PAMmapper(M,0,"eth_style",options.eth_style_symbol_mapping).demap(mlse_sig_hd);

    [~,numErrors,ber,~] = calc_ber(rx_bits.signal,tx_bits.signal,"skip_front",100,"skip_end",150,"returnErrorLocation",1);

    
    eq_package.ber          = ber;

    if options.showAnalysis
        eq_noise = eq_noise - mean(eq_noise.signal);

        rx_signal.spectrum("normalizeTo0dB",1,"fignum",250,"displayname","Rx Spectrum");

        Duobinary().encode(tx_symbols).spectrum("normalizeTo0dB",1,"fignum",250,"displayname","DB encoded reference");

        showEQNoisePSD(eq_noise,"fignum",250,"displayname",'Duobinary Target Noise after Equalization');

        fprintf('DB tgt BER: %.2e \n',ber);

        
    end


end