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From: | Tiankun Hu |
Subject: | [Discuss-gnuradio] integral frequency shift correcting in ofdm_frame_equalizer_vcvc_impl.cc |
Date: | Tue, 02 Sep 2014 22:14:27 +0800 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 |
Hi All,I found "ofdm_frame_equalizer_vcvc_impl.cc" use below code to correct integral freq shift(IFO) in freq domain, but as I known, the IFO only cause signal cyclic shifting in freq domain, why this block use gr_expj to correcting IFO in freq domain? might be blow code should be done in time domain.
// Correct the frequency shift on the symbols gr_complex phase_correction; for (int i = 0; i < frame_len; i++) {phase_correction = gr_expj(-M_TWOPI * carrier_offset * d_cp_len / d_fft_len * (i+1));
for (int k = 0; k < d_fft_len; k++) { out[i*d_fft_len+k] *= phase_correction; } } -- Thanks Tiankun
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