1mlib_SignalIFFTW_3(3MLIB) mediaLib Library Functions mlib_SignalIFFTW_3(3MLIB)
2
6 mlib_SignalIFFTW_3, mlib_SignalIFFTW_3_S16_S16_Mod, mlib_Sig‐
7 nalIFFTW_3_S16C_S16C_Mod, mlib_SignalIFFTW_3_S16_S16C_Mod, mlib_Sig‐
8 nalIFFTW_3_S16_Mod, mlib_SignalIFFTW_3_S16C_Mod, mlib_Sig‐
9 nalIFFTW_3_F32_F32, mlib_SignalIFFTW_3_F32C_F32C, mlib_Sig‐
10 nalIFFTW_3_F32_F32C, mlib_SignalIFFTW_3_F32, mlib_SignalIFFTW_3_F32C -
11 signal Inverse Fast Fourier Transform with windowing (IFFTW)
12
14 cc [ flag... ] file... -lmlib [ library... ]
15 #include <mlib.h>
16 mlib_status mlib_SignalIFFTW_3_S16_S16_Mod(mlib_s16 *dstr, mlib_s16 *dsti,
18 const mlib_s16 *srcr, const mlib_s16 *srci, const mlib_s16 *window,
19 mlib_s32 order);
20 mlib_status mlib_SignalIFFTW_3_S16C_S16C_Mod(mlib_s16 *dstc,
23 const mlib_s16 *srcc,
24 const mlib_s16 *window, mlib_s32 order);
25 mlib_status mlib_SignalIFFTW_3_S16_S16C_Mod(mlib_s16 *dstr,
28 const mlib_s16 *srcc,
29 const mlib_s16 *window, mlib_s32 order);
30 mlib_status mlib_SignalIFFTW_3_S16_Mod(mlib_s16 *srcdstr,
33 mlib_s16 *srcdsti,
34 const mlib_s16 *window, mlib_s32 order);
35 mlib_status mlib_SignalIFFTW_3_S16C_Mod(mlib_s16 *srcdstc,
38 const mlib_s16 *window,
39 mlib_s32 order);
40 mlib_status mlib_SignalIFFTW_3_F32_F32(mlib_f32 *dstr,
43 mlib_f32 *dsti,
44 const mlib_f32 *srcr, const mlib_f32 *srci, const mlib_f32 *window,
45 mlib_s32 order);
46 mlib_status mlib_SignalIFFTW_3_F32C_F32C(mlib_f32 *dstc,
49 const mlib_f32 *srcc,
50 const mlib_f32 *window, mlib_s32 order);
51 mlib_status mlib_SignalIFFTW_3_F32_F32C(mlib_f32 *dstr,
54 const mlib_f32 *srcc,
55 const mlib_f32 *window, mlib_s32 order);
56 mlib_status mlib_SignalIFFTW_3_F32(mlib_f32 *srcdstr,
59 mlib_f32 *srcdsti,
60 const mlib_f32 *window, mlib_s32 order);
61 mlib_status mlib_SignalIFFTW_3_F32C(mlib_f32 *srcdstc,
64 const mlib_f32 *window,
65 mlib_s32 order);
66
69 Each of the functions in this group performs Inverse Fast Fourier
70 Transform with windowing (IFFTW).
71 The FFTW functions use the following equation:
74 1 N-1
76 dst[k] = ---- SUM {src[n] * window[n] * exp(-j2*PI*n*k/N)}
77 C1 n=0
78 and the IFFTW functions use the following equation:
82 1 N-1
84 dst[n] = ---- SUM {src[k] * window[k] * exp(j2*PI*n*k/N)}
85 C2 k=0
86 where
90 k = 0, 1, ..., (N - 1)
92 n = 0, 1, ..., (N - 1)
93 N = 2**order
94 The signal FFTW/IFFTW functions can be categorized into four groups
98 according to the ScaleMode in the function names in the following form:
99 mlib_Signal[FFTW|IFFTW]_ScaleMode_OutType_InType_OpMode()
101 mlib_Signal[FFTW|IFFTW]_ScaleMode_DataType_OpMode()
102 The scaling factors C1 and C2 used in the equations are defined as fol‐
106 lows:
107 o For ScaleMode = 1, C1 = 1 and C2 = 2**order.
109 o For ScaleMode = 2, C1 = 2**order and C2 = 1.
111 o For ScaleMode = 3, C1 = C2 = 2**(order/2) when order is
113 even, or C1 = 2**((order+1)/2) and C2 = 2**((order-1)/2)
114 when order is odd.
115 o For ScaleMode = 4, C1 = 2**P and C2 = 2**Q, where P and Q
117 are adaptive scaling factors and are generated by the func‐
118 tions.
119 For functions with only real parts for the source signal, the imaginary
122 parts are assumed to be all zero. For functions with only real parts
123 for the destination signal, the imaginary parts are discarded. The
124 functions with only one data type in their names perform the operation
125 in place.
126
128 Each function takes some of the following arguments:
129 dstr Destination signal array that contains the real parts.
131 dsti Destination signal array that contains the imaginary parts.
134 srcr Source signal array that contains the real parts.
137 srci Source signal array that contains the imaginary parts.
140 dstc Complex destination signal array. dstc[2*i] contains the
143 real parts, and dstc[2*i+1] contains the imaginary parts.
144 srcc Complex source signal array. srcc[2*i] contains the real
147 parts, and srcc[2*i+1] contains the imaginary parts.
148 srcdstr Source and destination signal array that contains the real
151 parts.
152 srcdsti Source and destination signal array that contains the imagi‐
155 nary parts.
156 srcdstc Complex source and destination signal array. srcdstc[2*i]
159 contains the real parts, and srcdstc[2*i+1] contains the
160 imaginary parts.
161 window Window coefficient array with 2**order real elements. The
164 window coefficients are in Q15 format for the S16 data type,
165 or in float format for the F32 data type.
166 order Order of the transformation. The base-2 logarithm of the
169 number of data samples.
170
173 Each function returns MLIB_SUCCESS if successful. Otherwise it returns
174 MLIB_FAILURE.
175
177 See attributes(5) for descriptions of the following attributes:
178 ┌─────────────────────────────┬─────────────────────────────┐
183 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
184 ├─────────────────────────────┼─────────────────────────────┤
185 │Interface Stability │Committed │
186 ├─────────────────────────────┼─────────────────────────────┤
187 │MT-Level │MT-Safe │
188 └─────────────────────────────┴─────────────────────────────┘
189
191 mlib_SignalFFTW_1(3MLIB), mlib_SignalFFTW_2(3MLIB), mlib_Sig‐
192 nalFFTW_3(3MLIB), mlib_SignalFFTW_4(3MLIB), mlib_SignalIFFTW_1(3MLIB),
193 mlib_SignalIFFTW_2(3MLIB), mlib_SignalIFFTW_4(3MLIB), attributes(5)
194SunOS 5.11 2 Mar 2007 mlib_SignalIFFTW_3(3MLIB)