1 files changed, 73 insertions, 0 deletions
diff --git a/gr-fft/include/gnuradio/fft/fft_v.h b/gr-fft/include/gnuradio/fft/fft_v.h
new file mode 100644
index 0000000000..8fe4dba37e
--- /dev/null
+++ b/gr-fft/include/gnuradio/fft/fft_v.h
@@ -0,0 +1,73 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2004,2007,2008,2012,2018,2020 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ */
+
+#ifndef INCLUDED_FFT_FFT_V_H
+#define INCLUDED_FFT_FFT_V_H
+
+#include <gnuradio/fft/api.h>
+#include <gnuradio/sync_block.h>
+
+namespace gr {
+namespace fft {
+
+/*!
+ * \brief Compute forward or reverse FFT. complex vector in / complex vector out.
+ * \ingroup fourier_analysis_blk
+ *
+ * The FFT operation is defined for a vector \f$x\f$ with \f$N\f$ uniformly
+ * sampled points by
+ *
+ * \f[ X(a) = \sum_{k=0}^{N-1} x(a) \cdot e^{-j 2\pi k a / N} \f]
+ *
+ * \f$ X = FFT\{x\} \f$ is the the FFT transform of \f$x(a)\f$, \f$j\f$ is
+ * the imaginary unit, \f$k\f$ and \f$a\f$ range from \f$0\f$ to \f$N-1\f$.
+ *
+ * The IFFT operation is defined for a vector \f$y\f$ with \f$N\f$
+ * uniformly sampled points by
+ *
+ * \f[ Y(b) = \sum_{k=0}^{N-1} y(b) \cdot e^{j 2\pi k b / N} \f]
+ *
+ * \f$Y = IFFT\{y\}\f$ is the the inverse FFT transform of \f$y(b)\f$,
+ * \f$j\f$ is the imaginary unit, \f$k\f$ and \f$b\f$ range from \f$0\f$ to
+ * \f$N-1\f$.
+ *
+ * \b Note, that due to the underlying FFTW library, the output of a FFT
+ * followed by an IFFT (or the other way around) will be scaled i.e.
+ * \f$FFT\{ \, IFFT\{x\} \,\} =  N \cdot x \neq x\f$.
+ *
+ * \see http://www.fftw.org/faq/section3.html#whyscaled
+ */
+template <class T, bool forward>
+class FFT_API fft_v : virtual public sync_block
+{
+public:
+    typedef std::shared_ptr<fft_v<T, forward>> sptr;
+    /*! \brief
+     * \param[in] fft_size N.
+     * \param[in] window Window function to be used.
+     * \param[in] shift True moves DC carrier to the middle.
+     * \param[in] nthreads Number of underlying threads.
+     */
+    static sptr make(int fft_size,
+                     const std::vector<float>& window,
+                     bool shift = false,
+                     int nthreads = 1);
+
+    virtual void set_nthreads(int n) = 0;
+
+    virtual int nthreads() const = 0;
+
+    virtual bool set_window(const std::vector<float>& window) = 0;
+};
+
+} /* namespace fft */
+} /* namespace gr */
+
+#endif /* INCLUDED_FFT_FFT_V_H */