mlib_SignalIFFT_4_S16C_S16C(3mlib)

1mlib_SignalIFFT_4(3MLIB)  mediaLib Library Functions  mlib_SignalIFFT_4(3MLIB)
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NAME

6       mlib_SignalIFFT_4,         mlib_SignalIFFT_4_S16_S16,         mlib_Sig‐
7       nalIFFT_4_S16C_S16C, mlib_SignalIFFT_4_S16_S16C, mlib_SignalIFFT_4_S16,
8       mlib_SignalIFFT_4_S16C - signal Inverse Fast Fourier Transform (IFFT)
9

SYNOPSIS

11       cc [ flag... ] file... -lmlib [ library... ]
12       #include <mlib.h>
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14       mlib_status mlib_SignalIFFT_4_S16_S16(mlib_s16 *dstr, mlib_s16 *dsti,
15            const mlib_s16 *srcr, const mlib_s16 *srci,
16            mlib_s32 order, mlib_s32 *scale);
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19       mlib_status mlib_SignalIFFT_4_S16C_S16C(mlib_s16 *dstc,
20            const mlib_s16 *srcc,
21            mlib_s32 order, mlib_s32 *scale);
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24       mlib_status mlib_SignalIFFT_4_S16_S16C(mlib_s16 *dstr,
25            const mlib_s16 *srcc,
26            mlib_s32 order, mlib_s32 *scale);
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29       mlib_status mlib_SignalIFFT_4_S16(mlib_s16 *srcdstr,
30            mlib_s16 *srcdsti,
31            mlib_s32 order, mlib_s32 *scale);
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34       mlib_status mlib_SignalIFFT_4_S16C(mlib_s16 *srcdstc,
35            mlib_s32 order,
36            mlib_s32 *scale);
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38

DESCRIPTION

40       Each  of  the  functions  in  this  group performs Inverse Fast Fourier
41       Transform (IFFT).
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44       The following equation is used for forward FFT:
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46                   1   N-1
47         dst[k] = ---- SUM {src[n] * exp(-j2*PI*n*k/N)}
48                   C1  n=0
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52       and the following equation is used for inverse FFT (IFFT):
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54                   1   N-1
55         dst[n] = ---- SUM {src[k] * exp(j2*PI*n*k/N)}
56                   C2  k=0
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58
59
60       where
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62         k = 0, 1, ..., (N - 1)
63         n = 0, 1, ..., (N - 1)
64         N = 2**order
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68       The signal FFT/IFFT functions  can  be  categorized  into  four  groups
69       according to the ScaleMode in the function names in the following form:
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71         mlib_Signal[FFT|IFFT]_ScaleMode_OutType_InType_OpMode()
72         mlib_Signal[FFT|IFFT]_ScaleMode_DataType_OpMode()
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76       The scaling factors C1 and C2 used in the equations are defined as fol‐
77       lows:
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79           o      For ScaleMode = 1, C1 = 1 and C2 = 2**order.
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81           o      For ScaleMode = 2, C1 = 2**order and C2 = 1.
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83           o      For ScaleMode = 3, C1 = C2  =  2**(order/2)  when  order  is
84                  even,  or  C1  =  2**((order+1)/2) and C2 = 2**((order-1)/2)
85                  when order is odd.
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87           o      For ScaleMode = 4, C1 = 2**P and C2 = 2**Q, where  P  and  Q
88                  are  adaptive scaling factors and are generated by the func‐
89                  tions.
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92       For functions with only real parts for the source signal, the imaginary
93       parts  are  assumed  to be all zero. For functions with only real parts
94       for the destination signal, the  imaginary  parts  are  discarded.  The
95       functions  with only one data type in their names perform the operation
96       in place.
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PARAMETERS

99       Each function takes some of the following arguments:
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101       dstr       Destination signal array that contains the real parts.
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104       dsti       Destination signal array that contains the imaginary parts.
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107       srcr       Source signal array that contains the real parts.
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110       srci       Source signal array that contains the imaginary parts.
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113       dstc       Complex destination signal  array.  dstc[2*i]  contains  the
114                  real parts, and dstc[2*i+1] contains the imaginary parts.
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117       srcc       Complex  source  signal  array.  srcc[2*i] contains the real
118                  parts, and srcc[2*i+1] contains the imaginary parts.
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121       srcdstr    Source and destination signal array that contains  the  real
122                  parts.
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125       srcdsti    Source and destination signal array that contains the imagi‐
126                  nary parts.
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129       srcdstc    Complex source and destination  signal  array.  srcdstc[2*i]
130                  contains  the  real  parts,  and srcdstc[2*i+1] contains the
131                  imaginary parts.
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134       order      Order of the transformation. The  base-2  logarithm  of  the
135                  number of data samples.
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138       scale      Adaptive scaling factor.
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RETURN VALUES

142       The  function  returns MLIB_SUCCESS if successful. Otherwise it returns
143       MLIB_FAILURE.
144

ATTRIBUTES

146       See attributes(5) for descriptions of the following attributes:
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151       ┌─────────────────────────────┬─────────────────────────────┐
152       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
153       ├─────────────────────────────┼─────────────────────────────┤
154       │Interface Stability          │Committed                    │
155       ├─────────────────────────────┼─────────────────────────────┤
156       │MT-Level                     │MT-Safe                      │
157       └─────────────────────────────┴─────────────────────────────┘
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NAME

SYNOPSIS

DESCRIPTION

PARAMETERS

RETURN VALUES

ATTRIBUTES

SEE ALSO