% suggestions:
% [BPmode,DL,tf_mode] = [0 1 1] for lowpass
% [BPmode,DL,tf_mode] = [1 4 1] for bandpass (4-path DWA)
% [BPmode,DL,tf_mode] = [1 2 0] for bandpass (back-and-forth pointer)
Bits = 3;
BPmode = 0; %stimulus and delta-sigma converter type
% 0: lowpass, 1: bandpass
DACmode = 1; % 1 FOR DELTA-SIGMA DAC,
% 0 FOR DELTA-SIGMA ADC
%---- DWA SETUP ----
DL = 1; % delay in DWA
tf_mode=1; % Determines the type of mismatch noise transfer function
% 0: 1+z^(-DL), 1: 1-z^(-DL)
IDWAmode = 1; % 0: normal DWA
% 1: Incremental DWA (IDWA), i.e. ONE EXTRA UNIT ELEMENT
%DNL error related
Estd=0.01; % standard deviation of DNL errors
shape = 'sine'; k = 3; %the DNL error shape
% shape: k
% 'poly' polynomial order
% 'rand' random error, k is negligible, e.g. 0
% 'sine' sinusoid DNL error shape with k periods
N=pow2(Bits)-1; %number of elems
if IDWAmode
N=N+1;
end
random_dir = 1; % pointer direction can change as a random pattern, as
% long as the pattern length is D. See how the controlling
% sequence seq is created. If 1: random seq, else: ones.
%---- DWA SETUP END ----
if tf_mode==1
Bf = [1,zeros(1,DL-1),-1];
else
Bf = [1,zeros(1,DL-1),1];
end
%---- Simulation time
NT=pow2(17); %this many samples in simulation
fs = 1;ts= 1/fs; % sampling freq & interval
t=0:(NT-1)*ts;
Tfinal = t(end);
%----Simulation time END
%---- Stimulus
amp = 0.01;
fmult = 1/5; % Input sinusoid's place in the signal band:
% left side to right side 0->1. 0.5 is in the middle.
fb=fs*0.5/32; % signal band edge in lowpass mode
fsig = fmult*fb; % signal freq
J=fsig*NT/fs;
if abs(J-round(J))>0
J=round(J);
if rem(J,2)==0
J=J+1;
end
J = round(J);
end
if BPmode
J=J+NT/4;
end
fsig = J/NT*fs;
data = amp*cos(2*pi*fsig*t);
%---- Stimulus END
%---- DELTA SIGMA ----
%Oversampling ratio is set to 32, order is 2 for lowpass, 4 for bandpass.
%Also, loopfilter optimized for Bits = 3.
%Get DStoolbox to customize the DS loopfilter
if BPmode
A = [-1.056673642799789 -2.056673642799789 0 0;1 1 0 0;1 1 -0.943326357200210 -1.943326357200210;0 0 1 1];
B = [1 -1;0 0;0 0;0 0];
C = [0 -0.612223827873632 -1.897128681596029 -1.931825636131040];
D = [0 0];
else
A = [0.996788098211802 -0.003211901788198;1 1];
B = [1 -1;0 0];
C = [2.446130189023710 1.771892689428995];
D = [0 0];
end
%---- DELTA SIGMA END----
fsig = J/NT;
WLscale=0.5*(pow2(Bits)-1); %
WLoffset = sum(0:(pow2(Bits)-1))/pow2(Bits);
K=0:(N-1);
simin=[t.' data'];
%estimating the DWA spurs using stimulus and DNL error shape:
[n_hat,ck,E] = dwa_spur_est(Bits,BPmode,Estd,shape,k,Bf,data,IDWAmode,1);
%n_hat is the estimate
if random_dir
seqx = sign(randn(1,DL));
seqx(seqx==0)=1;
else
seqx=ones(1,DL);
end
if tf_mode
seq = seqx; % ...for plain DWA
else
% ...for BNF-dwa (see the ESL block)
seq = [seqx -seqx];
end
if DACmode
if IDWAmode
sim IDWAMOD_DAC
else
sim DWAMOD_DAC
end
else
if IDWAmode
sim IDWAMOD_ADC
else
sim DWAMOD_ADC
end
end
%---- PLOT
if not(exist('win','var')) || (exist('win','var') && length(win)~=NT)
%win=kaiser(NT,20);
win=hann(NT);
end
if BPmode
NS=pow2(log2(NT)-10);
else
NS=pow2(log2(NT)-9);
end
wins = hann(NT/NS);
HdB=20*log10(abs(fft(win.*simout,NT)/(sum(win)*0.5)));
MdB=20*log10(abs(fft(win.*mmnoise,NT)/(sum(win)*0.5)));
MestdB=20*log10(abs(fft(win.*n_hat.',NT)/(sum(win)*0.5)));
Hid_dB=20*log10(abs(fft(win.*(simout+mmnoise),NT)/(sum(win)*0.5)));
fvek=linspace(fs/NT,fs/2,NT/2);
figure
subplot(321)
plot(fvek,HdB(1:(NT*0.5)),'b')
title('output signal'),axis tight
xlabel('frequency'),ylabel('dB')
hold on
YLim=get(gca,'YLim');
if BPmode
plot((fs/4-fb/2)*[1 1],YLim,'k--',(fs/4+fb/2)*[1 1],YLim,'k--')
text(fs/4+fb/2,YLim(2)-10,'\leftarrowsignal band')
else
plot([fb fb],YLim,'k--')
text(fb,YLim(2)-10,'\leftarrowsignal band')
end
hold off
subplot(325)
plotflag = 1;
%switch modelname
% case {'DSDAC_none','DSADC_none'}
% plot(fvek,MdB(1:(NT*0.5)),'r')
% title('mismatch noise'),axis tight
% xlabel('frequency'),ylabel('dB')
%
% otherwise
plot(fvek,MestdB(1:(NT*0.5)),'c',fvek,MdB(1:(NT*0.5)),'r')
title('mismatch spur estimate & true mismatch noise'),axis tight
xlabel('frequency'),ylabel('dB')
%end
hold on
if BPmode
plot((fs/4-fb/2)*[1 1],YLim,'k--',(fs/4+fb/2)*[1 1],YLim,'k--')
text(fs/4+fb/2,YLim(2)-10,'\leftarrowsignal band')
else
plot([fb fb],YLim,'k--')
text(fb,YLim(2)-10,'\leftarrowsignal band')
end
hold off
set(gca,'YLim',YLim)
subplot(323)
plot(fvek,Hid_dB(1:(NT*0.5)),'k')
title('ideal output'),axis tight
xlabel('frequency'),ylabel('dB')
hold on
%YLim=get(gca,'YLim');
if BPmode
plot((fs/4-fb/2)*[1 1],YLim,'k--',(fs/4+fb/2)*[1 1],YLim,'k--')
text(fs/4+fb/2,YLim(2)-10,'\leftarrowsignal band')
else
plot([fb fb],YLim,'k--')
text(fb,YLim(2)-10,'\leftarrowsignal band')
end
hold off
set(gca,'YLim',YLim)
%Subplots below use Modulo Time Plot, see File ID: #22907
t=linspace(0,Tfinal,NT).';
subplot(322)
tt=mod(t,1/fsig);
[tt,index]=sort(tt);
yy=simout(index);
n_poly = 5;
warning off %#ok<WNOFF>
p=polyfit(tt,yy,n_poly);
warning on %#ok<WNON>
yest=polyval(p,tt);
plot(tt,yy,'b.',tt,yest,'--k','MarkerSize',4)
title('modulo time plot, output signal')
axis tight,legend('data','mean',1),
xlabel(['time, 1 period is ', num2str(1/fsig,2),'s. t_s = ',...
num2str(ts,2),'s'])
subplot(324)
qq = yy-yest;
plot(tt,qq,'m.','MarkerSize',4)
title('modulo time plot, qv. noise'), axis tight,xlabel('time, 1 period')
subplot(326)
plot(tt,mmnoise(index),'r.','MarkerSize',4)
axis tight, title('modulo time plot, mismatch noise')
xlabel('time, 1 period')
figure
subplot(211)
spectrogram(mmnoise,wins,length(wins)*0.5,[],1)
title('true mismatch noise spectrogram')
subplot(212)
spectrogram(n_hat,wins,length(wins)*0.5,[],1)
title('mismatch noise spurious noise estimate')
