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- fdet.m pass Xm

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- fdet_coarse.m use alternative approach
- fdet_wav.m added simple symbol decoding

git-svn-id: http://moon:8086/svn/matlab/trunk@28 801c6759-fa7c-4059-a304-17956f83a07c
This commit is contained in:
jens
2015-04-06 10:52:45 +00:00
parent c305a4c496
commit 2a65062181
3 changed files with 39 additions and 5 deletions
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ofdm/fdet.m
+2 -2
View File
@@ -1,10 +1,10 @@
function [omega, err, dmod, omega_coarse, omega_est] = fdet(x, N, Ng, off, omega_min, omega_step, omega_max)
function [omega, err, dmod, omega_coarse, omega_est, Xm] = fdet(x, N, Ng, off, omega_min, omega_step, omega_max)
%
K = fix((length(x)-Ng)/(N+Ng));
% Initial guess
omega_coarse = fdet_coarse(x, N, omega_min, omega_step, omega_max);
[omega_coarse, Xm] = fdet_coarse(x, N, Ng, omega_min, omega_step, omega_max);
phi_est = 0;
omega_est = omega_coarse;
ofdm/fdet_coarse.m
+20 -1
View File
@@ -1,5 +1,23 @@
function omega_coarse = fdet_coarse(x, N, omega_min, omega_step, omega_max)
function [omega_coarse, Xm] = fdet_coarse(x, N, Ng, omega_min, omega_step, omega_max)
Xm = zeros(N,1);
if 0
K = fix((length(x))/(N+Ng));
for k=1:K,
xp = x((k-1)*(N+Ng)+1:k*(N+Ng));
Xm = 0.5*Xm + fft(xp(Ng+1:N+Ng), N);
end
Nmax = ceil(omega_max*N)+1
[v, ii] = max(abs(Xm(1:Nmax)))
omega_coarse = (ii-1)/N;
else
omega_range = (omega_min:omega_step:omega_max);
for k=1:lge(omega_range)
@@ -9,3 +27,4 @@ end;
[v maxk] = max(abs(dmod));
omega_coarse = omega_range(maxk);
end
ofdm/fdet_wav.m
+17 -2
View File
@@ -42,16 +42,30 @@ cp_off = mod(ii, Ng+N)
% Detect CFO
fprintf('Perform frequency detection\n');
[omega, err, dmod, omega_coarse, omega_est] = fdet(x, N, Ng, cp_off, omega_min, omega_step, omega_max);
[omega, err, dmod, omega_coarse, omega_est, Xm] = fdet(x, N, Ng, cp_off, omega_min, omega_step, omega_max);
f_coarse = omega_coarse*fs
f_est = omega_est*fs
fprintf('Receive Symbols\n');
K = fix((length(x)-Ng)/(N+Ng));
for k=10:30
xp = x((k-1)*(N+Ng)+cp_off+1:k*(N+Ng)+cp_off);
Xp(:,k) = fft(xp(Ng+1:N+Ng), N);
end;
close all;
plot(abs(c)); grid;
figure;
bin = fix(N*750/48000)+1
plot(real(Xp(bin, :)), imag(Xp(bin, :)), '+'); grid;
figure;
plot(0:N-1, abs(Xm)); grid;
figure;
subplot(5,1,1)
plot(1:lge(omega), real(dmod)/N, 1:lge(omega), imag(dmod)/N, 1:lge(omega), abs(dmod)/N); grid; legend('Re', 'Im', 'abs()');
@@ -65,4 +79,5 @@ subplot(5,1,4)
plot(1:lge(omega), angle(dmod), '-', 1:lge(omega), diff(angle([0 dmod])), 'r-'); grid; legend('phi', 'dphi');
subplot(5,1,5)
plot(1:lge(omega), abs(dmod)/N - real(dmod)/N, '-'); grid; legend('diff');
plot(1:lge(omega), log10(abs(dmod) ./ (1E-6+abs(real(dmod)))), '-'); grid; legend('diff');