teqdemo.m

ADSL经典仿真程序

      hold on; 
      plot(D+1:D+Nb,B,'r','linewidth',2); hold off;
      set(gcf,'handlevisibility','callback')
      grid on
      xlabel('tap number')
      ylabel('amplitude')
      title([title_str,' TIR and SIR'])
      legend('SIR','TIR');
            
        else
      legend off
      hw100 = hw(1:100)/norm(hw);
      axhndlList = get(freqzHndl,'UserData');
      hndl = plot(hw100); 
      set(gcf,'handlevisibility','callback')
      grid on
      xlabel('tap number')
      ylabel('amplitude')
      title([title_str,' SIR'])
      legend('SIR');
        end
   elseif graphNum == 2
      legend off
      hndl = stem(W); 
      if Nw > 3
         hold on;
         plot(W,':');
         hold off
      end
      axis([0 Nw+1 1.1*min(W)*(min(W)<=0) 1.1*max(W)*(max(W)>0)])
      xlabel('tap number')
      ylabel('amplitude')
      title([title_str,' TEQ impulse response'])
      
   elseif graphNum == 3
      legend off
      plot(freqAxis(usedSubs),20*log10(abs(Fw(usedSubs))+eps));
      grid on
      axisSet = axis;
      axisSet(1) = min(freqAxis(usedSubs))-2;
      axisSet(2) = max(freqAxis(usedSubs))+2;
      axis(axisSet);
      xlabel('frequency bin number')
      ylabel('magnitude (dB)')
      title([title_str,' TEQ frequency response'])
      
   elseif graphNum == 4
      legend off
      plot(freqAxis(usedSubs),10*log10(subSNR(usedSubs)+eps))
      hold on;
      plot(freqAxis(usedSubs),10*log10(subMFB+eps),'r')
      hold off
      grid on
      axisSet = axis;
      axisSet(1) = min(freqAxis(usedSubs))-2;
      axisSet(2) = max(freqAxis(usedSubs))+2;
      axis(axisSet);
      xlabel('frequency')
      ylabel('magnitude (dB)')
      title([title_str,' achieved and upper-bound SNR'])
      legend('SNR','MFB',0);
      
   elseif graphNum == 5
      legend off
      maxAmp = max(abs(hw));
      plot(channel(1:500)/max(abs(channel))*maxAmp);
      hold on
      plot(hw(1:500),'r');
      hold off
      grid on	
      xlabel('discrete time (n)')
      ylabel('amplitude')
      title([title_str,' Original & Shortened Channel'])
      legend('original','shortened',0);         
      
   elseif graphNum == 6
      legend off
      plot(freqAxis(usedSubs),20*log10(noiseSpec+eps),'r')
      hold on
      plot(freqAxis(usedSubs),20*log10(colorNoiseaft(usedSubs)+eps))
      hold off
      grid on	
      axisSet = axis;
      axisSet(1) = min(freqAxis(usedSubs))-2;
      axisSet(2) = max(freqAxis(usedSubs))+2;
      axis(axisSet);
      xlabel('frequency')
      ylabel('magnitude (dB)')
      title([title_str,' Noise Power Spectrum'])
      legend('before TEQ','after TEQ',0);         
      
   elseif graphNum == 7
      legend off
      plot(Dmin:Dmax,10*log10(real(Dv(Dmin:Dmax))+eps))
      grid on	
      ylabel('objective function (e.g. MSE for MMSE method)')
      xlabel('delay')
      title([title_str,' Cost vs delay plot'])
      
   elseif graphNum == 8
      legend off
      plot(freqAxis(usedSubs),10*log10(abs(Fhw(usedSubs)).^2+eps));
      grid on
      axisSet = axis;
      axisSet(1) = min(freqAxis(usedSubs))-2;
      axisSet(2) = max(freqAxis(usedSubs))+2;
      axis(axisSet);
      ylabel('magnitude (dB)')
      xlabel('frequency')
      title([title_str,' Equalized Channel Frequency Response'])
   end
   
   set(gcf,'Pointer','arrow');
   return

   %save teq to a file
elseif strcmp(action,'saveteq');
   
    [filename,path]=uiputfile('*');
    if filename==0
        return;    
    end
    
    load singleteqresults;
    output=fopen([path,filename],'w');
    fprintf(output,'%s','optimal delay =');
    fprintf(output,' %d ;\n',TEQoptimalDelay);
    fprintf(output,'\n');
    fprintf(output,'%s\n','teq=[');
    for i=1:length(TEQequalizerTaps)
        fprintf(output,'%f \n',TEQequalizerTaps(i));
    end
    fprintf(output,'%s\n','];');
    fprintf(output,'\n');
    fprintf(output,'%s\n','feq=[');
    for i=1:length(TEQequalizedChannelFreqResp)
        fprintf(output,'%f \n',1/TEQequalizedChannelFreqResp(i));
    end
    fprintf(output,'%s\n','];');
    fclose(output);
    
    %save all parameters
elseif strcmp(action,'saveall')
    [filename,path]=uiputfile('*');
    if filename==0;
        return;
    end
    
    load singleteqresults;
    output=fopen([path,filename],'w');
    fprintf(output,'all the parameters are also saved into %s.mat\n',filename);
    fprintf(output,'%s','SIR length =');
    fprintf(output,' %d\n',TEQNb);
    fprintf(output,'%s','TEQ length =');
    fprintf(output,' %d;\n',TEQNw);
    fprintf(output,'%s','FFT size =');
    fprintf(output,' %d;\n',TEQN);
    fprintf(output,'%s','coding gain =');
    fprintf(output,' %f;\n',TEQCodingGain);
    fprintf(output,'%s','margin =');
    fprintf(output,' %d;\n',TEQMargin);
    fprintf(output,'%s','Dmin =');
    fprintf(output,' %d;\n',TEQDmin);
    fprintf(output,'%s','Dmax =');
    fprintf(output,' %d;\n',TEQDmax);
    fprintf(output,'%s','input power =');
    fprintf(output,' %f (dBm);\n',TEQInputPower);
    fprintf(output,'%s','AWGN power =');
    fprintf(output,' %f (dBm/Hz);\n',TEQAWGNPower);
    fprintf(output,'%s','loop number =');
    fprintf(output,' %d;\n',TEQLoopnum);
    fclose(output);
    str=sprintf(['save ', filename,' TEQNb TEQNw TEQN TEQCodingGain TEQMargin TEQDmin',...
            ' TEQDmax TEQInputPower TEQAWGNPower TEQLoopnum;']);
    eval(str);
    
   % get help
elseif strcmp(action,'info'),
   ttlStr = get(gcf,'name');
   myFig = gcf;
   
   topic1 =  ['Single-path TEQ design demo'];
   helptop1 = [...
     'This demo lets you design the time-domain equalizer (TEQ) and         '
     'frequency-domain equalizer (FEQ) in a conventional discrete multitone '
     'equalizer structure (cascade of TEQ, FFT, and FEQ) and analyze its    '
     'performance.                                                          '     
     '                                                                      '
     'Usage: Set parameters to desired values and hit the Calculate button. '
     '                                                                      '
     'The following TEQ design methods are supported:                       '
	 '  Minimum mean squared error -- unit energy constraint,               '
     '      N. Al-Dhahir and J. M. Cioffi, "Efficiently Computed            '
     '      Reduced-Parameter Input-Aided MMSE Equalizers for ML Detection: '
     '      A Unified Approach", IEEE Trans. on Info. Theory, vol. 42, pp.  '
     '      903-915, May 1996.                                              '
	 '  Minimum mean squared error -- unit tap constraint,                  ' 
     '      N. Al-Dhahir and J. M. Cioffi, "Efficiently Computed            '
     '      Reduced-Parameter Input-Aided MMSE Equalizers for ML Detection: '
     '      A Unified Approach", IEEE Trans. on Info. Theory, vol. 42, pp.  '
     '      903-915, May 1996.                                              '
     '  Maximum shortening signal-to-noise (SNR) ratio method,              '
     '      P. J. W. Melsa, R. C. Younce, and C. E. Rohrs, "Impulse Response'
     '      Shortening for Discrete Multitone Transceivers", IEEE Trans. on '
     '      Comm., vol. 44, pp. 1662-1672, Dec. 1996.                       '
     '  Maximum geometric signal-to-noise (SNR) method,                     '
     '      N. Al-Dhahir and J. M. Cioffi, "Optimum finite-length           '
     '      equalization for multicarrier transceivers", IEEE Trans. on     '
     '      Comm., vol 44. pp. 56-63, Jan. 1996.                            '
     '  Minimum intersymbol interference method,                            '
     '      G. Arslan, B. L. Evans, and S. Kiaei, "Equalization for         '
     '      Discrete Multitone Transceivers to Maximize Channel Capacity",  '
     '      IEEE Trans. on Signal Proc., submitted.                         '
     '  Maximum bit rate method,                                            '
     '      G. Arslan, B. L. Evans, and S. Kiaei, "Equalization for         '
     '      Discrete Multitone Transceivers to Maximize Channel Capacity",  '
     '      IEEE Trans. on Signal Proc., submitted.                         '
     '  Divide and conquer -- cancellation,                                 '
     '      B. Lu, L. D. Clark, G. Arslan, and B. L. Evans, "Fast           '
     '      Time-Domain Equalization for Discrete Multitone Modulation      '
     '      Systems", Proc. IEEE Digital Signal Processing Workshop,        '
     '      Oct. 15-18, 2000, Hunt, Texas.                                  '
     '  Divide and conquer -- minimization,                                 '
     '      B. Lu, L. D. Clark, G. Arslan, and B. L. Evans, "Fast           '
     '      Time-Domain Equalization for Discrete Multitone Modulation      '
     '      Systems", Proc. IEEE Digital Signal Processing Workshop,        '
     '      Oct. 15-18, 2000, Hunt, Texas.                                  '
     '  Matrix pencil design method,                                        '
     '      Y. Hua and T. K. Sarkar, "Matrix Pencil Method for Estimating   '
     '      Parameters of Exponentially Damped/Undamped Sinusoids in Noise" '
     '      IEEE Trans. Acoust. Speech Signal Processing, vol. 38, No. 5,   '
     '      pp. 814-824, May 1990                                           '
     '  Modified matrix pencil design method.                               '
     '      Y. Hua and T. K. Sarkar, "Matrix Pencil Method for Estimating   '
     '      Parameters of Exponentially Damped/Undamped Sinusoids in Noise" '
     '      IEEE Trans. Acoust. Speech Signal Processing, vol. 38, No. 5,   '
     '      pp. 814-824, May 1990                                           '
     '      and                                                             '
     '      B. Lu, D. Wei, B. L. Evans, and A. C. Bovik, "Improved Matrix   ' 
     '      Pencil Methods", Proc. IEEE Asilomar Conf. on Signals, Systems  '
     '      and Computers, Nov. 1-4, 1998, Pacific Grove, CA, vol. 2, pp.   '
     '      1433-1437.                                                      '
     '  Eigen approach design method                                        '
     '      B. Farhang-Boroujeny and M. Ding, "An Eigen-Approach to the     '
     '      Design of Near-Optimum Time Domain Equalizer for DMT            '
     '      Transceivers", IEEE Int. Conf. on Comm (ICC 99), vol. 2,        '
     '      pp. 937-941, 1999.                                              '
     '  Autoregressive Moving Average (ARMA) modeling design method         '
     '      P. J. W. Melsa, R. C. Younce, and C. E. Rohrs, "Impulse Response'
     '      Shortening for Discrete Multitone Transceivers", IEEE Trans. on '
     '      Comm., vol. 44, pp. 1662-1672, Dec. 1996.                       '
     '  Symmetric Maximum shortening signal-to-noise (SNR) ratio method     '
     '      R. K. Martin, C. R. Johnson, Jr, M. Ding, and B. L. Evans,      '
     '      "Exploiting Symmetry in Channel Shortening Equalizers",         '
     '      Proc. IEEE Int. Conf. on Acoustics, Speech, and Signal Proc.,   '
     '      April 6-10, 2003, Hong Kong, China.                             '];
   
   topic2 =  ['Design and Simulation Parameters'];
   helptop2 = [...
	 'On the top of the control window on the right is a pulldown menu      '
     'from which a design method can be chosen.                             '
	 'Below this pulldown menu are the following editable text windows      '
     'which are used to set the desired parameters,                         '
     '  Shortened impulse response (SIR) length. This is the desired length '
     '   of the channel after equalization. For example, it should be set   '
     '   to 33 (one plus the cyclic prefix length) for the ADSL standard.   '
     '  Time domain equalizer (TEQ) length. Defines the number of taps of   ' 
	 '   the TEQ.                                                           '
     '  Fast Fourier transform (FFT) size. Sets the FFT size used in DMT    '
     '   modulation. It is twice the number of subchannels.                 '
     '  Coding gain (dB). Defines a coding in dB used during capacity       '
     '   calculations.                                                      '
     '  Margin (dB). Sets the desired system margin in dB. This is also     '
     '   used in capacity calculations.                                     '
     '  Dmin and Dmax. The optimal delay is search in the interval between  '
     '   Dmin and Dmax.                                                     '
	 '  Input power (dBm). Defines the input signal power in dBm.           '
	 '  AWGN pow (dBm/Hz). Sets the amount of additive white Gaussian noise '
     '   in dBm/Hz. AWGN is added to the near-end crosstalk noise.          '
     '  CSA loop \# (1-8). Selects the desired channel to run the simulation'
     '   on. Currently 8 standard CSA loops are supported.                  '];
   
     topic3 =  ['Graphics'];
   helptop3 = [...
	 'Below the editable text windows is another pull-down menu which       '
     'is used to select the desired graph to be displayed.                  '
     'The following graphics can be selected:                               '
     '  Target and shortened channel. Displays the shortened channel impulse'	 
	 '   response and the target channel impulse response for the MMSE and  ' 
	 '   geometric SNR methods. For all other methods the location of the   ' 
     '   target window is displayed instead of a target impulse response.   '
     '  TEQ impulse response. Shows the impulse response of the TEQ.        '
     '  TEQ frequency response. Shows the TEQ in frequency domain.          '
     '  SNR and matched filter bound (MFB). The SNR and matched filter bound'
     '  to the SNR is displayed                                             '
     '   as a function of frequency (subchannels).                          '
     '  Original and shortened channel. Displays the channel impulse        '
     '   response before and after equalization.                            '
     '  Noise Power Spectrum. Shows the power spectrum of the noise which   '
     '   consists of NEXT noise plus AWGN.                                  '
     '  Delay Plot. Displays the performance measure of the method with     '
     '   respect to the delay.                                              '
     '  Equalized channel freq resp. Displays the frequency response of the '
     '   channel after equalization.                                        '];
 
   topic4 =  ['Performance Measures'];
   helptop4 = [...
'The two remaining buttons in the control frame are                    '
'   Info. Displays this help.                                          '
'   Calculate. Starts the calculation and performance evaluation of the'
'    TEQ.                                                              '
'The following performance measures are calculated and listed in the   '
'table:                                                                '
'   Rate. Gives the achievable bit rate with the given channel and TEQ '
'    settings.                                                         '
'   SNR. Shows the SNR at the output of the equalizer in dB.           '
'   SSNR. Shows the shortening SNR in dB. This is defined as the ratio '
'    of the energy of the shortened channel impulse response in the    '
'    target window the the energy outside the target window.           '
'   MSE. Gives the MSE for the MMSE and geometric SNR methods.         '
'   Delay. Shows the optimal delay for the system.                     '
'   Max Rate 1-FIR. Shows the absolute maximum achievable bit rate     '
'    given the channel and equalizer settings. It is basically the     '
'    capacity calculated from the matched filter bound.                '];
		 
   str =  { topic1 helptop1; topic2 helptop2; topic3 helptop3; topic4 helptop4 };
   
   helpwin(str,'Topic 1','Signal-path TEQ design demo')                   
   return  
   
else
   disp(sprintf( 'Internal ERROR: ''%s'' not recognized',action))
end