fdcheby2.m

matlabDigitalSigalProcess内有文件若干

        xd([2 5]) = newf1;
        L1.xdata = xd;
        f1.value = newf1;
        i = 1;
    case 2  % highpass
        newf2 = inbounds(xd(ind),[f1.value+minspacing Fs/2-minspacing]);
        xd([1 4]) = newf2;
        L1.xdata = xd;
        f2.value = newf2;
        i = 2;
    case 3  % bandpass
    % L1 xdata = [f2 f3 NaN f2 f3]
        if any(ind == [1 4])   % dragging f2
            newf2 = inbounds(xd(ind),[f1.value+minspacing f3.value-minspacing]);
            xd([1 4]) = newf2;
            L1.xdata = xd;
            f2.value = newf2;
            i = 2;
        else % dragging f3
            newf3 = inbounds(xd(ind),[f2.value+minspacing f4.value-minspacing]);
            xd([2 5]) = newf3;
            L1.xdata = xd;
            f3.value = newf3;
            i = 3;
        end
    case 4   % bandstop
    % L1 xdata = [0 f1 NaN 0 f1 NaN f4 Fs/2 NaN f4 Fs/2]
        if any(ind == [2 5])   % dragging f1
            newf1 = inbounds(xd(ind),[minspacing f2.value-minspacing]);
            xd([2 5]) = newf1;
            L1.xdata = xd;
            f1.value = newf1;
            i = 1;
        else % dragging f4
            newf4 = inbounds(xd(ind),[f3.value+minspacing Fs/2-minspacing]);
            xd([7 10]) = newf4;
            L1.xdata = xd;
            f4.value = newf4;
            i = 4;
        end
    end
    if minOrdCheckbox.value
%         [n,Fstop] = estimateOrder(type,Rp.value,Rs.value,Fs,...
%                  f1.value,f2.value,f3.value,f4.value);
%         order.value = n;
%         Fs1m.value = Fstop(1) * Fs/2;
%         if length(Fstop)>1
%             Fs2m.value = Fstop(2) * Fs/2;
%         end
    else
        fChangeMeas(i,type,Fs,Lresp,L1,L2,f1,f2,f3,f4,Rp,Rs,Fs1,Fs2)
        return
    end
    ax.xlimPassband = fdutil('xlimpassband',type,...
                         Fs,f1.value,f2.value,f3.value,f4.value);

    %fdutil('updateRanges',i,f1,f2,f3,f4)

%---------------------------------------------------------------------
% fdcheby2('L2drag',type,ind)
%  drag callback of L2 - stopband line
%  Inputs:
%     type - band configuration 1==low, 2=high, 3=pass, 4=stop
%     ind - index of vertex being dragged
case 'L2drag'
    type = varargin{2};
    ind = varargin{3};
    xd = L2.xdata;
    minspacing = Fs/500;
    switch type
    case 1  % lowpass
        newf2 = inbounds(xd(ind),[f1.value+minspacing Fs/2-minspacing]);
        xd(1) = newf2;
        L2.xdata = xd;
        f2.value = newf2;
        i = 2;
    case 2  % highpass
        newf1 = inbounds(xd(ind),[minspacing f2.value-minspacing]);
        xd(2) = newf1;
        L2.xdata = xd;
        f1.value = newf1;
        i = 1;
    case 3  % bandpass
    % L2 xdata = [0 f1 NaN f4 Fs/2]
        if ind == 2   % dragging f1
            newf1 = inbounds(xd(ind),[minspacing f2.value-minspacing]);
            xd(2) = newf1;
            L2.xdata = xd;
            f1.value = newf1;
            i = 1;
        else % dragging f4
            newf4 = inbounds(xd(ind),[f3.value+minspacing Fs/2-minspacing]);
            xd(4) = newf4;
            L2.xdata = xd;
            f4.value = newf4;
            i = 4;
        end
    case 4   % bandstop
    % L2 xdata = [f2 f3]
        if ind == 1   % dragging f2
            newf2 = inbounds(xd(ind),[f1.value+minspacing f3.value-minspacing]);
            xd(1) = newf2;
            L2.xdata = xd;
            f2.value = newf2;
            i = 2;
        else % dragging f3
            newf3 = inbounds(xd(ind),[f2.value+minspacing f4.value-minspacing]);
            xd(2) = newf3;
            L2.xdata = xd;
            f3.value = newf3;
            i = 3;
        end
    end
    % fdutil('updateRanges',i,f1,f2,f3,f4)
    
%---------------------------------------------------------------------
% fdcheby2('Rpdrag',type,ind)
%  drag callback of L1 - passband line
%  Inputs:
%     type - band configuration 1==low, 2=high, 3=pass, 4=stop
%     ind - index of segment being dragged
case 'Rpdrag'
    type = varargin{2};
    ind = varargin{3};
    yd = L1.ydata;
    
    below = yd(ind);
    if below >= 0 
        below = -.00001;
    elseif below < -10
        below = -10;
    end
    above = 0;
    
    newRp = above-below;

    if minOrdCheckbox.value
        if type ~= 4
        % 'ydata':[maxpass maxpass NaN minpass minpass]
            yd = [above above NaN below below];
        else
        % 'ydata': [ maxpass maxpass NaN minpass minpass NaN ...
        %                    maxpass maxpass NaN minpass minpass])
            yd = [above above NaN below below ...
                   NaN above above NaN below below ];
        end
        L1.ydata = yd;
        Rp.value = newRp;
        ylim = [below above];
        dyl = (ylim(2)-ylim(1))*.15;
        ax.ylimPassband = ylim + [-dyl/2 dyl/2];
    else
        Rp.value = newRp;
        RChangeMeas(1,type,Fs,Lresp,L1,L2,f1,f2,f3,f4,Rp,Rs,Fs1,Fs2)
    end
 
%---------------------------------------------------------------------
% fdcheby2('Rsdrag',type,ind)
%  drag callback of L2 - stopband line
%  Inputs:
%     type - band configuration 1==low, 2=high, 3=pass, 4=stop
%     ind - index of segment being dragged
case 'Rsdrag'
    type = varargin{2};
    ind = varargin{3};
  
    yd = L2.ydata;
    newRs = -yd(ind);
    if newRs < 0
        newRs = 0;
    end
    switch type
    case {1,2,4}
        L2.ydata = [-newRs -newRs];
    case 3
        L2.ydata = [-newRs -newRs NaN -newRs -newRs];
    end
    set(Rs,'value', newRs)
    
end  % of function switch-yard

%---------------------------------------------------------------------
% -------- LOCAL FUNCTIONS START HERE  --------- 
%---------------------------------------------------------------------

function sethelp
global minOrdCheckbox bandpop 
global passframe stopframe passframe1 stopframe1
global f1 f2 f3 f4 Fs1 Fs2 order Rp Rm pbspecs sbspecs
global Fs1m Fs2m
global ax L1 L2 Lresp
global Fs

% disp('setting help ... stub')

function [n,Fstop] = estimateOrder(type,Rp,Rs,Fs,f1,f2,f3,f4)
% [n,Fstop] = estimateOrder(type,Rp,Rs,Fs,f1,f2,f3,f4)
%   estimate filter order
%   takes the specifications as given by the input
%   parameters and estimates the order and stopband edge frequencies
%   needed to meet those specifications.
% Inputs:
%  type - 1,2,3,4 specifies band configuration
%  Rp, Rs passband, stopband ripple
%  Fs - sampling frequency
%  f1,f2  first two frequencies in ascending order
%  f3,f4 only needed if type == 3 or 4, remaining frequencies
%    f1,f2,f3,f4 are assumed between 0 and Fs/2 on input
% Outputs:
%  n - filter order
%  Fstop - filter band edges for cheby2, normalized to range [0...1]

if type == 1    % low pass
    Wp = f1;   Ws = f2;
elseif type == 2   % high pass
    Wp = f2;   Ws = f1;
elseif type == 3   % band pass
    Wp = [f2 f3];   Ws = [f1 f4];
elseif type == 4   % band stop
    Wp = [f1 f4];   Ws = [f2 f3];
end
[n,Fstop] = cheb2ord(Wp*2/Fs,Ws*2/Fs,Rp,Rs);
Fstop = Fstop(:)';   % make it a row 
 

function yd = passbandlimits(Rp)
% return ydata = [minpass maxpass] of passband 
%   given Rp decibels of ripple in passband (with maximum 1 in linear scale)
    above = 0; below = -Rp;
    yd = [below above];


function [maxpass,minpass,minstop] = getMagMeasurements(ff,Hlog,type,...
                                          f1,f2,f3,f4);
%getMagMeasurements
% Finds passband and stopband ripple for given band edges 
% given a filter's magnitude response
% Inputs:
%  ff - xdata of response
%  Hlog - magnitude of response at frequencies ff, in dB
%  type - band configuration (lp = 1, hp = 2, bp = 3, bs = 4)
%  f1, f2, f3, f4 - band edges (f3 and f4 ignored if type < 3)
%           in same units as ff
% Output:
%  fm - 2 or 4 element frequency vector in ascending order
    switch type
    case 1   % lowpass
        passInd = find(ff<=f1);
        stopInd = find(ff>=f2);
    case 2   % highpass
        stopInd = find(ff<=f1);
        passInd = find(ff>=f2);
    case 3   % bandpass
        stopInd = find((ff<=f1)|(ff>=f4));
        passInd = find((ff>=f2)&(ff<=f3));
    case 4   % bandstop
        passInd = find((ff<=f1)|(ff>=f4));
        stopInd = find((ff>=f2)&(ff<=f3));
    end
    maxpass = max(Hlog(passInd));
    minpass = min(Hlog(passInd));
    minstop = max(Hlog(stopInd));

function fm = getFreqMeasurements(ff,Hlog,type,Rp,Rs,Fstop)
%getFreqMeasurements
% Finds band edges for a given passband and stopband ripple
% given a filter's magnitude response
% Inputs:
%  ff - xdata of response (assumed a column vector)
%  Hlog - magnitude of response at frequencies ff, in dB
%               (assumed a column vector)
%  type - band configuration (lp = 1, hp = 2, bp = 3, bs = 4)
%  Rp - passband ripple, in dB
%  Rs - stopband attenuation in dB
%  Fstop - stopband edges, normalized to [0 Fs/2]
% Output:
%  fm - 2 or 4 element frequency (column) vector in ascending order
    passInd = find(Hlog(:)>=-Rp);
    ff = ff(:);
    switch type
    case 1   % lowpass
        fm = [ff(passInd(end)); Fstop];
    case 2   % highpass
        fm = [Fstop; ff(passInd(1))];
    case 3   % bandpass
        fm = [Fstop(1); ff(passInd([1 end])); Fstop(2)];
    case 4   % bandstop
        %  index of beginning of upper pass band
        i = min( find( ff(passInd)>=Fstop(1) ) );
        fm = [ff(passInd(i-1)); Fstop(1); Fstop(2); ff(passInd(i))];
    end

function fChangeMeas(i,type,Fs,Lresp,L1,L2,f1,f2,f3,f4,Rp,Rs,Fs1,Fs2)
%fChangeMeas - interactively track response when a frequency has changed
%  This function is meant to be called when the user
%     a) changes the f1,f2,f3, or f4 measurement
%  or b) drags the f1,f2,f3, f4 value
%  Xdata, Ydata, values of other frequencies and Rp and Rs are updated as
%  needed.
%  For cheby2, only the passband edges will change which can be any of
%  f1 through f4, depending on the type.
%  Inputs:
%    i - which frequency has just changed
%    type - band configuration (1 = lp, 2 = hp, 3 = bp, 4 = bs)
%    Fs - sampling frequency
%    Lresp, L1, L2 - fdline objects
%    f1,f2,f3,f4,Rp,Rs - fdmeas objects

    ff = Lresp.xdata;
    delf = ff(2)-ff(1);  % frequency spacing
    Hlog = Lresp.ydata;
    switch type
    case 1 % lowpass
           % passband edge
            ind = round(f1.value/delf) + 1;
            f1.value = ff(ind);
            Rp.value = -Hlog(ind);
    case 2  % highpass
      % passband edge
            ind = round(f2.value/delf) + 1;
            f2.value = ff(ind);
            Rp.value = -Hlog(ind);
    case 3 % bandpass
        switch i
        case 2     % lower passband edge
            ind = round(f2.value/delf) + 1;
            f2.value = ff(ind);
            Rp.value = -Hlog(ind);
        case 3     % upper passband edge
            ind = round(f3.value/delf) + 1;
            f3.value = ff(ind);
            Rp.value = -Hlog(ind);
        end
    case 4 % bandstop
        switch i
        case 1     % lower passband edge
            ind = round(f1.value/delf) + 1;
            f1.value = ff(ind);
            Rp.value = -Hlog(ind);
        case 4     % upper passband edge
            ind = round(f4.value/delf) + 1;
            f4.value = ff(ind);
            Rp.value = -Hlog(ind);
        end
    end
    if type >= 3  % find new freq. values in bp, bs case
        Fstop = get(Fs1,'value');
        if type > 2
            Fstop(2) = get(Fs2,'value');
        end
        fm = getFreqMeasurements(ff,Hlog,type,Rp.value,Rs.value,Fstop);
        switch type
        case 3 % bandpass - update f2 f3
                f2.value = fm(2);
                f3.value = fm(3);
        case 4 % bandstop - update f1 f4
                f1.value = fm(1);
                f4.value = fm(4);
        end
    end
    if type > 2
        fchange_ind = (i==(1:4)) * [1 4; 2 3; 2 3; 1 4];
    else
        fchange_ind = i;
    end
    updateLines(1,type,fchange_ind,f1,f2,f3,f4,Rp,Rs,Fs)