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发表于 2014-6-9 11:18:53
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% PLL Matlab Script
% B. Bereza
% PLL.m - V6.3 The modular version
% Created 19 Jan 1995
% Last Modified 28 Mar 2001
clear;
% Options ... if YES, set to "1". If NO, use anything else.
plot_OpenLoop=1; % Open Loop Plots (Stability)
overlay_OL=0; % Overlay successive plots (HOLD ON)
plot_Jtrans=1; % Closed Loop Plots
overlay_Jtrans=0; % Overlay successive closed loop plots (HOLD ON)
plot_JTOL=0; % Plot Jitter Tolerance
overlay_JTOL=0; % Overlay successive closed loop plots (HOLD ON)
plot_VCOphaseNoise=0; % Plot VCO phase Noise (in dBc/Hz)
plot_XOphaseNoise=0; % Plot XO phase Noise (in dBc/Hz)
plot_ROphaseNoise=0; % Plot Residual RO phase Noise (in dBc/Hz)
plot_CL_VCOphaseNoise=0;% Plot VCO phase Noise seen at output of PLL.
% Useful Math Constructs
flo=10; % low frequency for Plotting
fhi=1e9; % high frequency for Plotting
numpts=10000; % number of points for Plotting
f=logspace(log10(flo),log10(fhi),numpts);
w=2*pi*f;
% Givens & Loop Parameters
% fo=2e9
fo=2e9; % VCO free-running frequency
UI=1/fo; % Define Unit Interval
Ip=50e-6; % Charge-pump nominal current
DF=1/2; % Density Factor for Data Recovery of NRZ data
pfd_range=2*pi; % PFD range [rads] from 0 to edge
%hogge_range=1*pi; % Hogge range [rads] from 0 to edge
%Dlatch_range=.75*pi/2; % D-Latch range [rads] from 0 to edge
K2=1; % Additional Gain of Loop Filter
K3conv=1; % Gain inc. SEor DE conversion (2,1 or 1/2)
Kgm=1; %Transconductance [A/V] inc. SE or DE conversion.
fp1=50e10; % Parasitic Pole Frequency [Hz] (-3dB freq)
K3_OSC=2e9; %Nom % Gain sensitivity [Hz/V] of VCO or [Hz/A] for ICO
%K3_OSC=1.4e9; % Gain sensitivity [Hz/V] of VCO or [Hz/A] for ICO
Ko=2*pi*K3_OSC; % Gain sensitivity [rads/s/V] of V/ICO
N1=10; % Divider Ratio
% Simple Phase-Lead Loop Filter R-C & Cshunt
r2=2e3; % Parameters for transimpedance filter
c2=200e-12;
%cs=1*3e-12;
cs=10e-12;
% Frequency Dependent Calculations
Kpfd=Ip/pfd_range; % PFD [A/rad] Std. Resettable type (CSU)
%Khogge=DF*Ip/hogge_range; % Hogge [A/rad] Std. hogge PD. (CRU)
%KDlatch=DF*Ip/Dlatch_range; % D-latch [A/rad] PD
K1=Kpfd; % ***CHOOSE*** Gain of K1 [A/rad]
% Loop Filter (Simple one)
lf_num=[r2*c2 1]; % Numerator and Denominator
lf_den=[c2*cs*r2 cs+c2 0]; % in the form of s^n s^(n-1) ...s^0
% Loop Filter ( More complex) % Future Work
%lf_num=[r2*c2 1]; % Numerator and Denominator
%lf_den=[c2*cs*r2 cs+c2 0]; % in the form of s^n s^(n-1) ...s^0
F2=freqs(lf_num,lf_den,w); % ***CHOOSE*** which loop filter
% Transconductor or Gain Stage
Kgain_num=[1]; % Num and Den of parasitic pole only
Kgain_den=[1/(2*pi*fp1) 1];
F31=freqs(Kgain_num,Kgain_den,w); % Freq. characteristics
%K31=K3conv; % DC gain of the gain stage
K31=Kgm; % DC gain of the transconductor
% Current-Controlled or Voltage-Controlled Oscillator
Ko_num=[1]; Ko_den=[1 0]; % VCO/ICO has 1/s characterisic
F32=freqs(Ko_num,Ko_den,w); % Freq. Characteristics of the VCO/ICO
K32=Ko; % Gain of the VCO/ICO [rads/s/V] or [rads/s/A]
% Total VCO or ICO
K3=K31*K32; % Total gain (K3)
F3=F31.*F32; % Total Freq. response of the VCO.
% Divider
fref=fo/N1; % Fref is the compare frequency.
Tref=1/fref;
Fdiv=(1-exp(-1*j.*w./fref))./(j.*w./fref);
% The exact version (limited analysis possible)
ii=60;
for i=ii:-1:1, % The series expansion version
% Fdivx_num(ii+1-i)=(-1)^(i+1)/fac(i)*Tref^(i-1);
Fdivx_num(ii+1-i)=(-1)^(i+1)/factorial(i)*Tref^(i-1);
end
Fdivx_den=[1];
Fdivx=freqs(Fdivx_num,Fdivx_den,w);
Nx=N1./Fdivx; % Divider with Sampling Delay (expansion based)
N=N1./Fdiv; % Divider with Sampling Delay (pure) or PD-referred.
%N=N1; % Divider with no Sampling effects at all.
% Open Loop (Stability)
G=K1*K2*K3.*F2.*F3./N; % Pure method (No Bilinear possible later)
%Gs_num=K1*K2*K3*conv(conv(conv(lf_num,Kgain_num),Ko_num),Fdivx_num);
% Expansion method in S
%Gs_den=N1*(conv(conv(lf_den,Kgain_den),Ko_den));
%Gs=freqs(Gs_num,Gs_den,w); % Expansion method for comparison with Pure
% Closed Loop (Jitter Transfer) See Notes at end of this script.
A=K1*K2*K3.*F2.*F3; % Forward Loop
B=1./N; % Feedback Loop
Jtrans=A./(1+A.*B); % Jitter Transfer - Direct output of the VCO
H=1./N.*A./(1+A.*B); % Compare Transfer Function - VCO divided down.
M=1-H; % Phase Error Transfer Function
P0=1./(1+A.*B); % Power-Supply Noise Transfer Function at output of VCO
Vtrans=1./(1+A.*B); % VCO Perturbation transfer function
P3=1./N.*1./(1+A.*B); % Power-Supply Noise Transfer Function at PD output
Jtol=1./(1-H); % Jitter Tolerance
%Jtol=1./(1-Jtrans); % Jitter Tolerance Multiplier
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% PNoise Notes...
% PNoise - Takes the form..[Carrier dBm, dBc/Hz(f4),.. dBc/Hz(f0)]
% Notes: If Carrier dBm is not known, set to 0dBm.
% OR if quoted in dBc/Hz, set to 0dBm.
% dBc/Hz @ f4 (on 40dB/dec slope), freq at measurement
% set to -900 if there is no measurement with freq
% dBc/Hz @ f0 (thermal only, at freq. of measurement)
% XO Phase Noise
dBcxO=0; % carrier amplitude;
fc=125e6; % XO center frequency
XO=[dBcxO, -55,10, -82,100,-109,1000, -129,10000,-131,100000];
PN_XO=plotPN(f,XO); %spectrum created from above & plotted
XOX=10*log10(PN_XO);
%[jitdBc,jitUIrms,jitRMSw]=jitter(fc,f,PN_XO,10e3,80e6);
% determine jitter
%jitRMSw
% Residual Phase Noise
dBcrO=0; % carrier amplitude;
fc=125e6/N1; % XO center frequency
RO=[dBcrO, -51,10,-82,100,-109.0,1000,-129,10000,-131,100000];
PN_RO=plotPN(f,RO); %spectrum created from above & plotted
XRX=10*log10(PN_RO);
%[jitdBc,jitUIrms,jitRMSr]=jitter(fc,f,PN_RO,10e3,80e6);
% determine jitter
%jitRMSr
%semilogx(f,-dBcO+30+10*log10(PN_XO));
% Residual PD Phase Noise
% NF and Gain of forward loop required. Use kTB, with B=1
% VCO Phase Noise
% See Note below on possible overestimation of
% phase noise jitter and spectrum Note4.
dBcO=0; % carrier amplitude;
fc=2e9; % VCO center frequency
VCO=[dBcO, -56,10,-82,100,-109,1000,-129,10000,-132,1e7];
PN_VCO=plotPN(f,VCO); %spectrum created from above & plotted
XXX=10*log10(PN_VCO);
%[jitdBc,jitUIrms,jitRMSg]=jitter(fc,f,PN_VCO,10e0,10e6);
% determine jitter
%jitRMSg
%semilogx(f,XXX);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Total Noise from Most Sources... (Have not included Wireless stuff)
% NTM - I should want to put in AM to PM (V-Phi) Noise
% Remember... Keep to PSDs so PN_VCO should be multiplied by abs(Vtrans)^2
PNtot_vco=PN_VCO.*(abs(Vtrans)).^2;
PNtot_ref=PN_XO.*(abs(Jtrans)).^2;
PNtot_div=PN_RO.*(abs(Jtrans)).^2;
PNtot=(PN_XO+PN_RO).*(abs(Jtrans)).^2+PN_VCO.*(abs(Vtrans)).^2;
[jitdBc,jitUIrms,jitRMSv]=jitter(fc,f,PNtot_vco,10e0,10e6);
% determine jitter jitRMSv
if plot_CL_VCOphaseNoise==1
figure
semilogx(f,10*log10(abs(PNtot_vco)),'r');
hold on
semilogx(f,10*log10(abs(PNtot_ref)),'c');
semilogx(f,10*log10(abs(PNtot_div)),'g');
semilogx(f,10*log10(abs(PNtot)))
end
% Plotting (Set this at beginning of program)
if plot_OpenLoop==1
plotOL(G,f,overlay_OL);
end
if plot_Jtrans==1
plotCL(Jtrans,H,M,f,overlay_Jtrans);
end
if plot_JTOL==1
% plotJTOL(Jtol,f,overlay_JTOL);
plotJTOL(Jtol,H,M,f,overlay_JTOL);
end
if plot_ROphaseNoise==1
figure;
semilogx(f,XRX);
end
if plot_XOphaseNoise==1
figure;
semilogx(f,XOX);
end
if plot_VCOphaseNoise==1
figure;
semilogx(f,XXX);
end
%Notes:
%1) See Documentation on this program for further details.
%2) Power supply noise transfer functions:
%Power supply attenuation is defined as theta_out/theta_disturbance,where
%theta_out occurs at the same location as theta_disturbance.
% Dividing down by any N (ie. along
%the divder chain will produce Pxx.
%3)
%4) Phase Noise near transition points will approach 6dB too
%much due to superposition as opposed to theoretical.
%In reality, this is real!, so do not subtract it.
这个是整个PLL噪声的程序。 |
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发表于 2014-6-9 11:03:06
