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- TX: process data at symbol rate

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- RX: removed kdown stuff (hardcode to 4), fixed redundant down sampling for base band processing

git-svn-id: http://moon:8086/svn/matlab/trunk@37 801c6759-fa7c-4059-a304-17956f83a07c
This commit is contained in:
jens
2015-04-19 20:06:40 +00:00
parent d4ddc6eac4
commit 65fc129d88
2 changed files with 17 additions and 14 deletions
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ofdm/ofdm_rx.m
+9 -10
View File
@@ -5,25 +5,22 @@ function [x] = ofdm_rx(filename, foff, knoise_dB, with_cir)
% ofdm_rx('xv.wav', 0, -400, 0) % ofdm_rx('xv.wav', 0, -400, 0)
% or ofdm_rx('yv.wav', 0, -400, 0) % or ofdm_rx('yv.wav', 0, -400, 0)
close all;
drm_mode = 'B'; drm_mode = 'B';
drm_bw = '10k'; drm_bw = '10k';
[ofdm_drm_params, ofdm_spec_occ] = drm_params(drm_mode, drm_bw); [ofdm_drm_params, ofdm_spec_occ] = drm_params(drm_mode, drm_bw);
close all;
pre_mix = 0; pre_mix = 0;
Kdown = 4; fs = 12000;
fs = 48000/Kdown; N = 256;
fc = fs/4; Ng = 64;
N = 1024/Kdown;
Ng = 256/Kdown;
[carrier_pilot, phi_pilot, mag_pilot] = getRefFreq(drm_mode); [carrier_pilot, phi_pilot, mag_pilot] = getRefFreq(drm_mode);
[carrier_time, phi_time, mag_time] = getRefTime(drm_mode); [carrier_time, phi_time, mag_time] = getRefTime(drm_mode);
h_cir = [0 0 .1 -.2 .5 .2 -.1 0 0 ]; h_cir = [0 0 .1 -.2 .5 .2 -.1 0 0 ];
close all;
% Generate signal % Generate signal
[xwav fs_ nbits] = wavread(filename); [xwav fs_ nbits] = wavread(filename);
@@ -37,10 +34,12 @@ elseif (ndim == 1)
x = xwav.*exp(-j*(2*pi*(0.25-foff/fs_)*(0:len-1)')); x = xwav.*exp(-j*(2*pi*(0.25-foff/fs_)*(0:len-1)'));
hlp = FIRCalcLowpass(12000/fs_, 33); hlp = FIRCalcLowpass(12000/fs_, 33);
x = filter(hlp, 1, x); x = filter(hlp, 1, x);
% Downsample
x = x(1:4:length(x));
else else
error('Cannot read file!'); error('Cannot read file!');
end end
x = x(1:Kdown:length(x));
if with_cir if with_cir
x = filter(h_cir, 1, x); x = filter(h_cir, 1, x);
@@ -53,7 +52,7 @@ wavwrite(xout,fs,nbits,'ofdm_rx.wav');
x = x + sqrt(0.5)*10^(knoise_dB/20)*(randn(size(x)) + j*randn(size(x))); x = x + sqrt(0.5)*10^(knoise_dB/20)*(randn(size(x)) + j*randn(size(x)));
K = fix((length(x)-Ng)/(N+Ng)); K = fix((length(x))/(N+Ng))-1;
% Timing coarse % Timing coarse
cp_off_ = []; cp_off_ = [];
ofdm/ofdm_tx.m
+8 -4
View File
@@ -15,8 +15,8 @@ M_QAM = 64;
RCWIN_ROLLOFF = 0.125; RCWIN_ROLLOFF = 0.125;
% Params % Params
fa = 48000; fa = 12000;
T = 4/fa; T = 1/fa;
[ofdm_params, ofdm_spec_occ] = drm_params(mode, bandwidth); [ofdm_params, ofdm_spec_occ] = drm_params(mode, bandwidth);
@@ -107,12 +107,16 @@ grid;
plot(wng); grid; plot(wng); grid;
% Modulate on carrier % Modulate on carrier
yc = exp(j*2*pi.*(0:length(xv)-1)*0.25) .* xv; xup = upsample(xv, 4);
hlp = FIRCalcLowpass(0.25, 129);
xup = filter(hlp, 1, xup);
yc = exp(j*2*pi.*(0:length(xup)-1)*0.25) .* xup;
yv = real(yc) + imag(yc); yv = real(yc) + imag(yc);
xv = conj(xv')./abs(max(xv)); xv = conj(xv')./abs(max(xv));
yv = yv'./max(yv); yv = yv'./max(yv);
wavwrite(0.9*yv,fa,16,'yv.wav') wavwrite(0.9*yv,4*fa,16,'yv.wav')
wavwrite(0.9*[real(xv) imag(xv)],fa,16,'xv.wav') wavwrite(0.9*[real(xv) imag(xv)],fa,16,'xv.wav')