shameem
Member level 5
Hi,
I am working on thesynchronisation of DAB(digital audio broadcating) receiver. It is based on the OFDM technology. I have a captured signal of dab. The signal is captured with the IF 38.912 Mhz. Then i used undersampling technique to sample the signal at 8.192 Mhz sampling frequency. After this, i multiplied the captured samples with the sequences {1,0,-1,0} and {0,-1,0,1} to downconvert this signal to the baseband. Then i applied two lpf on both the I & Q streams and decimated the sequences by 4 to perform 2048 point FFT.
According to all the papers i have gone through, they say that now i should multiply the demodulated sequence with the conj of this known sequence(PRS) and then i should do a 2048 point IFFT to get the impulse response.In this impulse response, i should get a peak value at some offset in time.
But when i do all this process, i do not get any peak value in the impulse response instead i get a noise like signal having many peaks of nearly equal strength.
I also do not get any peak in the autocorelation process also.
If anybody have some idea about this problem, please help me suggest some way out.
I am working on thesynchronisation of DAB(digital audio broadcating) receiver. It is based on the OFDM technology. I have a captured signal of dab. The signal is captured with the IF 38.912 Mhz. Then i used undersampling technique to sample the signal at 8.192 Mhz sampling frequency. After this, i multiplied the captured samples with the sequences {1,0,-1,0} and {0,-1,0,1} to downconvert this signal to the baseband. Then i applied two lpf on both the I & Q streams and decimated the sequences by 4 to perform 2048 point FFT.
According to all the papers i have gone through, they say that now i should multiply the demodulated sequence with the conj of this known sequence(PRS) and then i should do a 2048 point IFFT to get the impulse response.In this impulse response, i should get a peak value at some offset in time.
But when i do all this process, i do not get any peak value in the impulse response instead i get a noise like signal having many peaks of nearly equal strength.
I also do not get any peak in the autocorelation process also.
If anybody have some idea about this problem, please help me suggest some way out.
