Manual Pages for UNIX Operating System command usage for man mlib_SignalNLMSFilterInit_S16S_S16S

mediaLib Library Functions           mlib_SignalNLMSFilter(3MLIB)



NAME
     mlib_SignalNLMSFilter,    mlib_SignalNLMSFilterInit_S16_S16,
     mlib_SignalNLMSFilterInit_S16S_S16S,
     mlib_SignalNLMSFilterInit_F32_F32,
     mlib_SignalNLMSFilterInit_F32S_F32S,
     mlib_SignalNLMSFilter_S16_S16_Sat,
     mlib_SignalNLMSFilter_S16S_S16S_Sat,
     mlib_SignalNLMSFilter_F32_F32,
     mlib_SignalNLMSFilter_F32S_F32S,
     mlib_SignalNLMSFilterNonAdapt_S16_S16_Sat,
     mlib_SignalNLMSFilterNonAdapt_S16S_S16S_Sat,
     mlib_SignalNLMSFilterNonAdapt_F32_F32,
     mlib_SignalNLMSFilterNonAdapt_F32S_F32S,
     mlib_SignalNLMSFilterFree_S16_S16,
     mlib_SignalNLMSFilterFree_S16S_S16S,
     mlib_SignalNLMSFilterFree_F32_F32,
     mlib_SignalNLMSFilterFree_F32S_F32S  - normalized least mean
     square (NLMS) adaptive filtering

SYNOPSIS
     cc [ flag... ] file... -lmlib [ library... ]
     #include 

     mlib_status mlib_SignalNLMSFilterInit_S16_S16(void **filter,
          const mlib_f32 *flt, mlib_s32 tap, mlib_f32 beta);


     mlib_status mlib_SignalNLMSFilterInit_S16S_S16S(void **filter,
          const mlib_f32 *flt, mlib_s32 tap, mlib_f32 beta);


     mlib_status mlib_SignalNLMSFilterInit_F32_F32(void **filter,
          const mlib_f32 *flt, mlib_s32 tap, mlib_f32 beta);


     mlib_status mlib_SignalNLMSFilterInit_F32S_F32S(void **filter,
          const mlib_f32 *flt, mlib_s32 tap, mlib_f32 beta);


     mlib_status mlib_SignalNLMSFilter_S16_S16_Sat(mlib_s16 *dst,
          const mlib_s16 *src, const mlib_s16 *ref, void *filter, mlib_s32 n);


     mlib_status mlib_SignalNLMSFilter_S16S_S16S_Sat(mlib_s16 *dst,
          const mlib_s16 *src, const mlib_s16 *ref, void *filter, mlib_s32 n);


     mlib_status mlib_SignalNLMSFilter_F32_F32(mlib_f32 *dst,
          const mlib_f32 *src, const mlib_f32 *ref, void *filter, mlib_s32 n);






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mediaLib Library Functions           mlib_SignalNLMSFilter(3MLIB)



     mlib_status mlib_SignalNLMSFilter_F32S_F32S(mlib_f32 *dst,
          const mlib_f32 *src, const mlib_f32 *ref, void *filter, mlib_s32 n);


     mlib_status mlib_SignalNLMSFilterNonAdapt_S16_S16_Sat(mlib_s16 *dst,
          const mlib_s16 *src, const mlib_s16 *ref, void *filter, mlib_s32 n);


     mlib_status mlib_SignalNLMSFilterNonAdapt_S16S_S16S_Sat(mlib_s16 *dst,
          const mlib_s16 *src, const mlib_s16 *ref, void *filter, mlib_s32 n);


     mlib_status mlib_SignalNLMSFilterNonAdapt_F32_F32(mlib_f32 *dst,
          const mlib_f32 *src, const mlib_f32 *ref, void *filter, mlib_s32 n);


     mlib_status mlib_SignalNLMSFilterNonAdapt_F32S_F32S(mlib_f32 *dst,
          const mlib_f32 *src, const mlib_f32 *ref, void *filter, mlib_s32 n);


     void mlib_SignalNLMSFilterFree_S16_S16(void *filter);


     void mlib_SignalNLMSFilterFree_S16S_S16S(void *filter);


     void mlib_SignalNLMSFilterFree_F32_F32(void *filter);


     void mlib_SignalNLMSFilterFree_F32S_F32S(void *filter);


DESCRIPTION
     The normalized LMS adaptive algorithm is summarized as  fol-
     lows:

         1.   Initialize the weights Wk(i), i = 0, 1, ..., tap  -
              1.

         2.   Initialize previous source elements Xo(i), i  =  0,
              1, ..., tap - 1.

         3.   Read Xk(t) from src and Yk(t) from ref, t =  0,  1,
              ..., n - 1.

         4.   Compute filter output: nk = sum(Wk(i) * Xk(t - i)),
              i  =  0,  1,  ...,  tap - 1. If i > t, use previous
              source elements stored in the Xo vector.

         5.   Compute source elements power: Pwk = sum(Xk(t -  i)
              * Xk(t - i)), i = 0, 1, ..., tap - 1. If i > t, use
              previous source elements stored in the Xo vector.



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mediaLib Library Functions           mlib_SignalNLMSFilter(3MLIB)



         6.   Store filter output : dst[t] = nk.

         7.   Compute the error estimate: Ek = Yk - nk.

         8.   Compute factor BE0 = 2 * beta * Ek / Pwk.

         9.   Update filter weights: Wk(i) += BE0 * Xk(t - i),  i
              = 0, 1, ..., tap - 1. If i > t, use previous source
              elements stored in the Xo vector.

         10.  Next t, go to step 3.

         11.  Store N ending source elements in  previous  source
              elements vector Xo: if N > n, N = n; else N = tap.


     Each of the FilterInit functions allocates  memory  for  the
     internal  filter  structure and converts the parameters into
     the internal representation.


     Each of the  Filter  functions  applies  the  NLMS  adaptive
     filter on one signal packet and updates the filter states.


     Each of the FilterNoAdapt functions applies the NLMS  filter
     on  one  signal  packet  and  updates  the filter states but
     without changing the filter weights.


     Each of the FilterFree functions releases the  memory  allo-
     cated for the internal filter structure.

PARAMETERS
     Each of the functions takes some of the following arguments:

     filter    Internal filter structure.


     flt       Filter coefficient array.


     tap       Taps of the filter.


     beta      Error weighting factor. 0 < beta < 1.


     dst       Destination signal array.






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mediaLib Library Functions           mlib_SignalNLMSFilter(3MLIB)



     src       Source signal array.


     ref       Reference or "desired" signal array.


     n         Number of samples in the source signal array.


RETURN VALUES
     Each of the FilterInit, Filter and FilterNonAdapt  functions
     returns  MLIB_SUCCESS  if  successful.  Otherwise it returns
     MLIB_FAILURE. The FilterFree  functions  don't  return  any-
     thing.

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|


SEE ALSO
     mlib_SignalLMSFilter(3MLIB), attributes(5)























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