Question about fetchdt.h


  • Hi!

    I'm trying to implement reduced clock operation and trying to understand fetchdt.h.

    I have some questions

    1. in body of FetchDMADataTouchDownSampled44, there is already "downsample from 40MHz to 20MHz" (below code)

    Is it already implement half-clock operation? If not, what is purpose of this part?

        // Downsample from 40MHz to 20MHz
        // Mem2VcsL and Mem2VcsH work together to downsample sequential 2 signal block into one signal block
        Mem2VcsL(*(SignalBlock*)p40MStream , block[0], block[1], block[2], block[3]);  // vcs is  4 complex16 samples
        Mem2VcsH(*((SignalBlock*)p40MStream + 1), block[3], block[4], block[5], block[6]);
        return hr;  // return S_OK if succed



    2. in body of resampler.resample ( in 44Mto40M.h ), it use LinearTableR, LinearTableL for downsampling 44M to 40M.

      What is mean of LinearTableR(and L)? What's mean of value of element in LinearTableR?

      I want to implement half-clock operation, than should I change this LinearTableR?

    3. in Mem2VcsH fuctio, what is mean of m128FirstHalfMask and ~0 which is an element in m128FirstHalfMask? (in fetchdt.h)

    Tuesday, October 25, 2011 9:28 AM

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