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Altera_Forum's avatar
Altera_Forum
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11 years ago

Synchronization of 2 Decimating FIRs

Hello,

In my design, I'm using complex I/Q signal. Before feeding a correlator, I need to filter it out with a decimation factor=16.

Correlator needs to have on its inputs synchronized both I and Q components. In simulation both filters produce "valid" signal with the same phase. Can I assume, that in hardware they will be also synchronized? And feed the "valid" input of the correlator by "and" function of "valid" outputs of the filters?

Or it would be better to use 2 d-latches, and to strobe the correlators input by free running counter?

regards,

carter

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    11 years ago

    --- Quote Start ---

    Hello,

    In my design, I'm using complex I/Q signal. Before feeding a correlator, I need to filter it out with a decimation factor=16.

    Correlator needs to have on its inputs synchronized both I and Q components. In simulation both filters produce "valid" signal with the same phase. Can I assume, that in hardware they will be also synchronized? And feed the "valid" input of the correlator by "and" function of "valid" outputs of the filters?

    Or it would be better to use 2 d-latches, and to strobe the correlators input by free running counter?

    regards,

    carter

    --- Quote End ---

    If your two valid out of both filters are identical and in phase then you don't need ANDing them or any latches. Just use one of filter valid out as input to next stage. If you are not sure about your own simulation then why?