function varargout = eqber_graphics(plotType, varargin)% EQBER_GRAPHICS - Generate and update plots for the eqber demo.%   [hBER, hLegend, legendString, hLinSpec, hDfeSpec, hErrs, ...%       hText1, hText2, hFit, hEstPlot] = ...%       eqber_graphics('init', chnl, EbNo, idealBER, nBits)%   generates handles to be used later in the simulation run.%   Inputs:%      chnl         - channel impulse response%      EbNo         - vector of Eb/No values%      idealBER     - ideal BPSK BER values corresponding to the EbNo vector%      nBits        - number of bits in a data block%   Outputs:%      hBER         - handle to a line in the BER plot%      hLegend      - vector of handles corresponding to visible legend entries %                     in the BER plot%      legendString - cell array of legend strings for the BER plot%      hLinSpec     - line handle for the spectrum plot of the linearly %                     equalized signal%      hDfeSpec     - line handle for the spectrum plot of the DFE equalized%                     signal%      hErrs        - line handle to a bar plot showing burst error performance%      hText1       - first text handle for the burst error plot%      hText2       - second text handle for the burst error plot%      hFit         - line handle for fitted BER curves%      hEstPlot     - line handle for the channel estimate plot%%%   hSpecPlot = eqber_graphics('sigspec', eqType, hSpecPlot, nBits, PreD)%   updates the spectrum plots for adaptively equalized signals.%   Inputs:%      eqType       - 'linear', 'dfe', or 'mlse'%      hSpecPlot    - line handle for the spectrum plot%      nBits        - number of bits in a data block%      PreD         - equalized, predetected signal%   Outputs:%      hSpecPlot - line handle for the spectrum plot%%%   [hErrs, hText1, hText2] = eqber_graphics('bursterrors', eqType, ...%      mlseType, firstErrPlot, refMsg, testMsg, nBits, hErrs, hText1, hText2)%      updates the burst error performance plots.%   Inputs:%      eqType       - 'linear', 'dfe', or 'mlse'%      mlseType     - 'ideal' or 'imperfect'%      firstErrPlot - flag indicating whether the current plot is the first %                     burst error performance plot for the current equalizer%      refMsg       - transmitted signal, used to find bit errors%      testMsg      - received signal, used to find bit errors%      nBits        - number of bits in a data block%      hErrs        - line handle to a bar plot showing burst error performance%      hText1       - first text handle for the burst error plot%      hText2       - second text handle for the burst error plot%   Outputs:%      hErrs        - line handle to a bar plot showing burst error performance%      hText1       - first text handle for the burst error plot%      hText2       - second text handle for the burst error plot%%%   [hBER, hLegend, legendString] = eqber_graphics('simber', eqType, ...%      mlseType, firstBlk, EbNoIdx, EbNo, BER, hBER, hLegend, legendString)%      updates the BER plot.%   Inputs:%      eqType       - 'linear', 'dfe', or 'mlse'%      mlseType     - 'ideal' or 'imperfect'%      firstBlk     - flag indicating whether the current data block is the%                     first one being processed for the current equalizer type%      EbNoIdx      - index over the range of EbNo%      EbNo         - vector of Eb/No values%      hBER         - line handle to the current line in the BER plot%      hLegend      - vector of handles corresponding to visible legend entries %                     in the BER plot%      legendString - cell array of legend strings for the BER plot%   Outputs:%      hBER         - line handle to the current line in the BER plot%      hLegend      - vector of handles corresponding to visible legend entries %                     in the BER plot%      legendString - cell array of legend strings for the BER plot%%%   hFit = eqber_graphics('fitber', eqType, mlseType, hFit, EbNoIdx, EbNo, BER)%   updates the curve fit to the simulated BER data.%   Inputs:%      eqType       - 'linear', 'dfe', or 'mlse'%      mlseType     - 'ideal' or 'imperfect'%      hFit         - line handle to the current BER curve fit%      EbNoIdx      - index over the range of EbNo%      EbNo         - vector of Eb/No values%      BER          - vector of BER values corresponding to the Eb/No values%   Outputs:%      hFit         - line handle to the current BER curve fit%%%   hEstPlot = eqber_graphics('chnlest', chnlEst, chnlLen, excessEst, ...%   nBits, firstEstPlot, hEstPlot) updates the channel estimate plot for the%   MLSE algorithm.%   Inputs:%      chnlEst      - impulse response of estimated channel%      chnlLen      - length of estimated channel impulse response%      excessEst    - the difference between the length of the estimated channel%                     impulse response and the actual channel impulse response%      nBits        - number of bits in a data block%      firstEstPlot - flag indicating whether the current channel estimate plot %                     is the first one%      hEstPlot     - line handle to the channel estimate plot%   Outputs:%      hEstPlot     - line handle to the channel estimate plot%   Copyright 1996-2004 The MathWorks, Inc.%   $Revision: 1.1.4.1 $  $Date: 2004/06/30 23:03:09 $% ------------------------------------------------------------------------------switch plotType    case 'init'        [chnl, EbNo, idealBER, nBits] = deal(varargin{:});                % Plot the unequalized channel        plot_uneqchnl(chnl);                % Plot the ideal BPSK BER curve        [hBER, hLegend, legendString] = plot_idealber(EbNo, idealBER);                % Initialize a figure to display the linearly equalized signal spectrum        hLinSpec = plot_sigspec('init', 'linear', nBits);                % Initialize a figure to display the DFE equalized signal spectrum        hDfeSpec = plot_sigspec('init', 'dfe', nBits);                % Initialize a figure to display the burst error performance of the        % linear equalizer, DFE equalizer, MLSE equalizer with an ideal channel        % estimate, and an MLSE equalizer with an imperfect channel estimate        [hErrs, hText1, hText2] = plot_bursterrors('init', [], [], []);                % Initialize a dummy line handle for BER curve fitting        set(0, 'CurrentFigure', get(get(hBER, 'Parent'), 'Parent'));        hFit = semilogy(0, 1);                % Initialize a figure to display the frequency response of the imperfect        % channel estimate        hEstPlot = plot_chnlest('init', nBits);                        varargout{1}  = hBER;        varargout{2}  = hLegend;        varargout{3}  = legendString;        varargout{4}  = hLinSpec;        varargout{5}  = hDfeSpec;        varargout{6}  = hErrs;        varargout{7}  = hText1;        varargout{8}  = hText2;        varargout{9}  = hFit;        varargout{10} = hEstPlot;            case 'sigspec'        hSpecPlot = plot_sigspec('update', varargin{:});         varargout{1} = hSpecPlot;            case 'bursterrors'        [hErrs, hText1, hText2] = plot_bursterrors('update', varargin{:});        varargout{1} = hErrs;        varargout{2} = hText1;        varargout{3} = hText2;            case 'simber'        [hBER, hLegend, legendString] = plot_simber(varargin{:});        varargout{1} = hBER;        varargout{2} = hLegend;        varargout{3} = legendString;            case 'fitber'        hFit = plot_fitber(varargin{:});        varargout{1} = hFit;            case 'chnlest'        hEstPlot = plot_chnlest('update', varargin{:});        varargout{1} = hEstPlot;end% ------------------------------------------------------------------------------function plot_uneqchnl(chnl);% PLOT_UNEQCHNL - Plot the frequency response of the unequalized channel%   Inputs:%      chnl - channel impulse response% Generate a normalized frequency vector from -pi to piFFTlen   = 2048;freq = [-FFTlen/2 : (FFTlen/2)-1]' * (2*pi/FFTlen);% Generate the normalized frequency responsechnlLen  = length(chnl);FFTchnl = [chnl; zeros(FFTlen - chnlLen, 1)];magFFT = abs(fft(FFTchnl));plot(freq, 20*log10(fftshift(magFFT/max(magFFT))));axis([-3.14 3.14 -40 10]);pos = figposition([0 45 33 33]);  % for multiple screen resolutionsset(gcf, 'Position', pos);title('Unequalized Channel Frequency Response');xlabel('Normalized Frequency (rad/s)');ylabel('Normalized Magnitude Squared (dB)');drawnow;% ------------------------------------------------------------------------------function [hBER, hLegend, legendString] = plot_idealber(EbNo, idealBER)% PLOT_IDEALBER - Plot the BER for ideal BPSK%   Inputs:%      EbNo         - vector of Eb/No values%      idealBER     - ideal BER values corresponding to the EbNo values%   Outputs:%      hBER         - line handle to the current line in the BER plot%      hLegend      - vector of handles corresponding to visible legend entries %                     in the BER plot%      legendString - cell array of legend strings for the BER plotfigure; pos = figposition([33.3 45 36 36]); figBER = gcf;set(figBER, 'Position', pos);  % for multiple screen resolutionsaxBER = axes;set(axBER, 'YScale'    , 'log', ...           'XLim'      , [0 16], ...           'YLim'      , [1e-6 1], ...           'XTick'     , [0:2:16], ...           'XGrid'     , 'on', ...           'YGrid'     , 'on', ...           'YMinorGrid', 'off', ...           'Title'     , text('String','Equalizer BER Comparison'), ...           'XLabel'    , text('String', 'Eb/No (dB)'), ...           'YLabel'    , text('String', 'BER'));hold on; hBER = semilogy(EbNo, idealBER);legendString = 'Ideal BPSK      ';hLegend = hBER;legend(hLegend, legendString, 'Location', 'SouthWest');drawnow;% ------------------------------------------------------------------------------function h = plot_sigspec(plotType, eqType, varargin)% PLOT_SIGSPEC - Initialize or update a plot of an equalized signal spectrum%   Inputs:%      plotType - 'init' or 'update' %      eqType   - 'linear' or 'dfe'%      h        - line handle to the signal spectrum plot%      nBits    - number of bits in a data block%      PreD     - equalized, predetected signal%   Outputs:%      h        - line handle to the signal spectrum plot        % On initialization, set up all the figure properties and make the figure% invisible.  On update, simply make the figure visible and reset the values of% the plotted data.switch plotType    case 'init'        % Generate a frequency vector        nBits = varargin{1};        freq = [-nBits/2 : 4 : (nBits/2)-1]' * (2*pi/nBits);                figure; h = plot(freq, freq);  % initialize with dummy data        fig = get(get(h, 'Parent'), 'Parent');        set(fig, 'Visible', 'off');        axis([-3.14 3.14 -40 10]);        xlabel('Normalized Frequency (rad/s)');        ylabel('Normalized Power Spectrum (dB)');                if (strcmpi(eqType, 'linear'))            pos  = figposition([0 5 33 33]);            figTitle = 'Linearly Equalized Signal Power Spectrum';            color    = [0 0 0];        elseif (strcmpi(eqType, 'dfe'))            pos  = figposition([33.3 5 33 33]);            figTitle = 'Decision Feedback Equalized Signal Power Spectrum';            color    = [1 0 0];        end        title(figTitle);        set(fig, 'Position', pos);  % for multiple screen resolutions        set(h, 'Color', color);