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CMSIS-DSP
Version 1.4.9
CMSIS DSP Software Library
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arm_rfft_instance_q31 S = {fftLenReal, fftLenBy2, ifftFlagR, bitReverseFlagR, twidCoefRModifier, pTwiddleAReal, pTwiddleBReal, pCfft}; arm_rfft_instance_q15 S = {fftLenReal, fftLenBy2, ifftFlagR, bitReverseFlagR, twidCoefRModifier, pTwiddleAReal, pTwiddleBReal, pCfft};where
fftLenReal
is the length of the real transform; fftLenBy2
length of the internal complex transform. ifftFlagR
Selects forward (=0) or inverse (=1) transform. bitReverseFlagR
Selects bit reversed output (=0) or normal order output (=1). twidCoefRModifier
stride modifier for the twiddle factor table. The value is based on the FFT length; pTwiddleAReal
points to the A array of twiddle coefficients; pTwiddleBReal
points to the B array of twiddle coefficients; pCfft
points to the CFFT Instance structure. The CFFT structure must also be initialized. Refer to arm_cfft_radix4_f32() for details regarding static initialization of the complex FFT instance structure.