diff --git a/ofdm/ofdm_rx.m b/ofdm/ofdm_rx.m
index 3b6eb2b..714101b 100644
--- a/ofdm/ofdm_rx.m
+++ b/ofdm/ofdm_rx.m
@@ -451,7 +451,9 @@ hlp = FIRCalcLowpass(0.25, 129);
 fprintf('.');
 xup = filter(hlp, 1, xup);
 
-y = exp(j*2*pi.*(0:length(xup)-1)'*0.25) .* xup;
+fprintf('.');
+y = exp(j*2*pi.*(0:length(xup)-1)'*(0.25+0.25*df_track/fs)) .* xup;
+wavwrite(0.8*y,fs*4,nbits,'rx_y.wav');
 
 fprintf('.');
 tt = equalizer.f_err_ ./ max(abs(equalizer.f_err_));