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some refactor done, second order PLL to be corrected
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@arnauochoa
arnauochoa committed Dec 30, 2020
1 parent 7f01152 commit a944ee6
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71 changes: 38 additions & 33 deletions main.m
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Original file line number Diff line number Diff line change
Expand Up @@ -2,28 +2,28 @@
%blabla

%% Initializations
prn = 20; % PRN index
duration = 5000e-3; % sec - 200 times the PRN
tR = 1e-3; % sec - PRN period
prn = 20; % - PRN index
duration = 5000e-3; % sec 200 times the PRN
tR = 1e-3; % sec PRN period
prnLength = 1023; % samples of the PRN
kDelay = 8945; % samples of the PRN
fDoppler = 1755; % Hz Doppler shift
fIF = 4.348e6; % Hz Intermediate frequency
fs = 23.104e6; % Hz Sampling frequency
B = fs/2; % Hz RF front-end BW
Bl = 10; % Hz Equivalent bandwidth of the PLL
tI = 1e-3; % sec Integration time
sLength = duration/tR * prnLength; % Signal length in code samples
tC = tR/prnLength;
tVec = 0:1/fs:duration-1/fs; % Vector of time
isFirstOrder = 0;
Kpll = 0.01; % Kpll = [0.01 0.05 0.1 0.5]
tVec = 0:1/fs:duration-1/fs; % Vector of time
order = 2; % - Order of the PLL. 1 or 2
Kpll = 0.01; % - Gain of the 1st order PLL
Bl = 10; % Hz Equivalent bandwidth of the 2nd order PLL
thresHist = 500e-3; % sec Threshold to compute the variance of Vd

%% Generation of synthetic signal
A = 1; % mW/s Amplitude of the synthetic signal
cno = 60; % dbHz C/N0 of the synthetic signal cn0 = [35 40 45 50 60];
phi = pi/4;
cno = 60; % dbHz C/N0 of the synthetic signal
phi = deg2rad(10);
% phi = linspace(0, 2*pi, length(tVec));
% phi = sin(2*pi*5*tVec);
signal = syntheticSignal(prn, kDelay, A, cno, tC, fIF, phi, tVec, fDoppler, B);
Expand All @@ -49,6 +49,7 @@
Q = zeros(duration/tR,1);
k = 2;
iTs = 0:1/fs:tI-1/fs;
% iTs = 1/fs:1/fs:tI;
for t=1:nSamples:length(signal)-nSamples
In = signal(t:t+nSamples-1) ...
.*cm(t:t+nSamples-1) ... %add doppler in code
Expand All @@ -60,26 +61,28 @@
I(k) = (1/nSamples)*sum(In);
Q(k) = (1/nSamples)*sum(Qn);

if isFirstOrder
Vd(k) = - atan2( Q(k), I(k) );
theta(t+nSamples:t+2*nSamples-1) = theta(t:t+nSamples-1) + Kpll * Vd(k);
else
Vd(k) = - atan2( Q(k), I(k) );

K1 = 60/23 * Bl * tI;
K2 = 4/9 * K1^2;
K3 = 2/27 * K1^3;

if k-2 <= 0, Vc2 = 0; Vd2 = 0;
else, Vc2 = Vc(k-2); Vd2 = Vd(k-2); end

Vc(k) = 2*Vc(k-1) - ...
Vc2 + ...
(K1+K2+K3) * Vd(k)/(2*pi*tI) - ...
(2*K1+K2) * Vd(k-1)/(2*pi*tI) + ...
K1 * Vd2/(2*pi*tI);

theta(t+nSamples:t+2*nSamples-1) = theta(t:t+nSamples-1) + 2*pi*Vc(k)*iTs;
Vd(k) = - atan2( Q(k), I(k) );

switch order
case 1 % First order
theta(t+nSamples:t+2*nSamples-1) = theta(t:t+nSamples-1) + Kpll * Vd(k);
case 2 % Second order
K1 = 60/23 * Bl * tI;
K2 = 4/9 * K1^2;
K3 = 2/27 * K1^3;

if k-2 <= 0, Vc2 = 0; Vd2 = 0;
else, Vc2 = Vc(k-2); Vd2 = Vd(k-2); end

Vc(k) = 2*Vc(k-1) - ...
Vc2 + ...
(K1+K2+K3) * Vd(k)/(2*pi*tI) - ...
(2*K1+K2) * Vd(k-1)/(2*pi*tI) + ...
K1 * Vd2/(2*pi*tI);

theta(t+nSamples:t+2*nSamples-1) = theta(t:t+nSamples-1) + 2*pi*Vc(k)*iTs;
otherwise
error('Invalid order value');
end
k = k + 1;
end
Expand Down Expand Up @@ -110,10 +113,12 @@
xlabel('Time (ms)'); ylabel('Vd(t) (deg)');
title('Discriminator output');

figure; plot(kVec,Vc*180/pi);
xlabel('Time (ms)'); ylabel('Vc(t) (Hz)');
title('NCO input signal');

if order == 2
figure; plot(kVec,Vc*180/pi);
xlabel('Time (ms)'); ylabel('Vc(t) (Hz)');
title('NCO input signal');
end

figure; plot(kVec,I, 'b'); hold on;
plot(kVec, Q, 'r');
xlabel('Time (ms)');
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59 changes: 31 additions & 28 deletions main.m~
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Original file line number Diff line number Diff line change
Expand Up @@ -2,28 +2,28 @@ clear; close all; clc;
%blabla

%% Initializations
prn = 20; % PRN index
duration = 5000e-3; % sec - 200 times the PRN
tR = 1e-3; % sec - PRN period
prn = 20; % - PRN index
duration = 5000e-3; % sec 200 times the PRN
tR = 1e-3; % sec PRN period
prnLength = 1023; % samples of the PRN
kDelay = 8945; % samples of the PRN
fDoppler = 1755; % Hz Doppler shift
fIF = 4.348e6; % Hz Intermediate frequency
fs = 23.104e6; % Hz Sampling frequency
B = fs/2; % Hz RF front-end BW
Bl = 30; % Hz Equivalent bandwidth of the PLL
tI = 1e-3; % sec Integration time
sLength = duration/tR * prnLength; % Signal length in code samples
tC = tR/prnLength;
tVec = 0:1/fs:duration-1/fs; % Vector of time
isFirstOrder = 1;
Kpll = 0.01; % Kpll = [0.01 0.05 0.1 0.5]
tVec = 0:1/fs:duration-1/fs; % Vector of time
order = 1; % - Order of the PLL. 1 or 2
Kpll = 0.01; % - Gain of the 1st order PLL
Bl = 10; % Hz Equivalent bandwidth of the 2nd order PLL
thresHist = 500e-3; % sec Threshold to compute the variance of Vd

%% Generation of synthetic signal
A = 1; % mW/s Amplitude of the synthetic signal
cno = 60; % dbHz C/N0 of the synthetic signal cn0 = [35 40 45 50 60];
phi = pi/3;
phi = deg2rad(10);
% phi = linspace(0, 2*pi, length(tVec));
% phi = sin(2*pi*5*tVec);
signal = syntheticSignal(prn, kDelay, A, cno, tC, fIF, phi, tVec, fDoppler, B);
Expand All @@ -49,6 +49,7 @@ I = zeros(duration/tR,1);
Q = zeros(duration/tR,1);
k = 2;
iTs = 0:1/fs:tI-1/fs;
% iTs = 1/fs:1/fs:tI;
for t=1:nSamples:length(signal)-nSamples
In = signal(t:t+nSamples-1) ...
.*cm(t:t+nSamples-1) ... %add doppler in code
Expand All @@ -60,26 +61,28 @@ for t=1:nSamples:length(signal)-nSamples
I(k) = (1/nSamples)*sum(In);
Q(k) = (1/nSamples)*sum(Qn);

if isFirstOrder
Vd(k) = atan2( Q(k), I(k) ) - pi;
theta(t+nSamples:t+2*nSamples-1) = theta(t:t+nSamples-1) + Kpll * Vd(k);
else
Vd(k) = atan2( Q(k), I(k) );

K1 = 60/23 * Bl * tI;
K2 = 4/9 * K1^2;
K3 = 2/27 * K1^3;

if k-2 <= 0, Vc2 = 0; Vd2 = 0;
else, Vc2 = Vc(k-2); Vd2 = Vd(k-2); end

Vc(k) = 2*Vc(k-1) - ...
Vc2 + ...
(K1+K2+K3) * Vd(k)/(2*pi*tI) - ...
(2*K1+K2) * Vd(k-1)/(2*pi*tI) + ...
K1 * Vd2/(2*pi*tI);

theta(t+nSamples:t+2*nSamples-1) = theta(t:t+nSamples-1) + 2*pi*Vc(k)*iTs;
Vd(k) = - atan2( Q(k), I(k) );

switch order
case 1 % First order
theta(t+nSamples:t+2*nSamples-1) = theta(t:t+nSamples-1) + Kpll * Vd(k);
case 2 % Second order
K1 = 60/23 * Bl * tI;
K2 = 4/9 * K1^2;
K3 = 2/27 * K1^3;

if k-2 <= 0, Vc2 = 0; Vd2 = 0;
else, Vc2 = Vc(k-2); Vd2 = Vd(k-2); end

Vc(k) = 2*Vc(k-1) - ...
Vc2 + ...
(K1+K2+K3) * Vd(k)/(2*pi*tI) - ...
(2*K1+K2) * Vd(k-1)/(2*pi*tI) + ...
K1 * Vd2/(2*pi*tI);

theta(t+nSamples:t+2*nSamples-1) = theta(t:t+nSamples-1) + 2*pi*Vc(k)*iTs;
otherwise
error('Invalid order value');
end
k = k + 1;
end
Expand Down

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