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  1. #1
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    PN code noncoherent acquisition frequency offset problem

    Hello,
    I tried to find out that in PN code noncoherent acquisition, how the frequency offset is detected efficiently. I googled the related papers, but what I found is nothing more than saying" using a bank of filters tuned to different central frequency".
    Anybody could refer me to certain book or papers where it is described in more details?

    Thanks!

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  2. #2
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    Re: PN code noncoherent acquisition frequency offset problem

    If I understand ur problem correctly .. U r trying to Acquire a PN code having some doppler (frequency offset) from base band.

    The best approach I can think is FFT acquisition technique if u r using DSP processor for acquisition . U take coherent data and then do non coherent integration for reducing noise, finally perform FFT on it and do bin search for maximum peak ad compare it with ur acquisition threshold..
    if ( Max peak is > Acquisition threshold )
    then frequency ofset is approx = FFT bin number * frq per bin )
    else
    change the chip of local PN code and repeat the process

    I hope this helps

    Please "Click HELPED me )

    Funky [:D]


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  3. #3
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    PN code noncoherent acquisition frequency offset problem

    Thanks very much.

    And can you recommend some book or papers to me?

    Added after 37 minutes:

    By the way, how about the frequency offset caused by the transmitter center frequency drift.
    In many cases, I think this is more significant than Doppler effect



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  4. #4
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    Re: PN code noncoherent acquisition frequency offset problem

    if there is some frequency drift from the transmitter clock side .. then u can always have phase lock loop 2nd or 3rd order to cater that. Its an easy job again to do that..

    U may read CDMA Engineering handbook for this ..

    If u have any specific theory then state it

    [U can click helped me] [:D]

    Funky


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  5. #5
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    PN code noncoherent acquisition frequency offset problem

    I am going to check it out
    Thanks dude!

    By the way, how could the 2nd or 3rd order PLL get ride of the frequency offset?
    Since it is impossible to do the carrier recovery in DSSS due to the low SNR.



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