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https://github.com/gnss-sdr/gnss-sdr
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70 lines
2.3 KiB
C
70 lines
2.3 KiB
C
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/*----------------------------------------------------------------------------------------------*/
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/*! \file fft.h
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//
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// FILENAME: fft.h
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//
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// DESCRIPTION: Defines the FFT class.
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//
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// DEVELOPERS: Gregory W. Heckler (2003-2009)
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//
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// LICENSE TERMS: Copyright (c) Gregory W. Heckler 2009
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//
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// This file is part of the GPS Software Defined Radio (GPS-SDR)
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//
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// The GPS-SDR is free software; you can redistribute it and/or modify it under the terms of the
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// GNU General Public License as published by the Free Software Foundation; either version 2 of
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// the License, or (at your option) any later version. The GPS-SDR is distributed in the hope that
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// it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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// more details.
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//
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// Note: Comments within this file follow a syntax that is compatible with
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// DOXYGEN and are utilized for automated document extraction
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//
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// Reference:
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*/
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/*----------------------------------------------------------------------------------------------*/
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#ifndef FFT_H_
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#define FFT_H_
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#include "gps_sdr_defines.h"
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#include "gps_sdr_signal_processing.h"
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#define MAX_RANKS (16)
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/*! @ingroup CLASSES
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@brief /xyzzy */
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class FFT
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{
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private:
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MIX *W; //!< Twiddle lookup array for FFT
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MIX *iW; //!< Twiddle lookup array for iFFT
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int32 *BRX; //!< Re-order temp array
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int32 *BR; //!< Re-order index array
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int32 N; //!< Length (should be 2^N!!!)
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int32 M; //!< Log2(N) (number of ranks)
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int32 R[16]; //!< Programmable rank scaling
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void initW(); //!< Initialize twiddles
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void initBR(); //!< Initialize re-order array
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void doShuffle(CPX *_x); //!< Do bit-reverse shuffling
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public:
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FFT(); //!< Initialize FFT
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FFT(int32 _N); //!< Initialize FFT for 2^N
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FFT(int32 _N, int32 _R[MAX_RANKS]); //!< Initialize FFT for 2^N, with ranks
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~FFT(); //!< Destructor
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void doFFT(CPX *_x, bool _shuf); //!< Forward FFT, decimate in time
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void doiFFT(CPX *_x, bool _shuf); //!< Inverse FFT, decimate in time
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void doFFTdf(CPX *_x, bool _shuf); //!< Forward FFT, decimate in frequency
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void doiFFTdf(CPX *_x, bool _shuf); //!< Inverse FFT, decimate in frequency
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};
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#endif /*FFT_H_*/
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