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124 lines
2.6 KiB
C++
124 lines
2.6 KiB
C++
/*
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* Polyphase synthesis filter
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*
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* Copyright (C) 2012-2014 Tom Tsou <tom@tsou.cc>
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* Copyright (C) 2015 Ettus Research LLC
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*
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* SPDX-License-Identifier: AGPL-3.0+
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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* See the COPYING file in the main directory for details.
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*/
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#include <stdlib.h>
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#include <math.h>
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#include <assert.h>
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#include <string.h>
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#include <cstdio>
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#include <iostream>
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#include "Synthesis.h"
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extern "C" {
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#include "fft.h"
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#include "convolve.h"
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}
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static void interleave(float **in, size_t ilen,
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float *out, size_t m)
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{
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size_t i, n;
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for (i = 0; i < ilen; i++) {
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for (n = 0; n < m; n++) {
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out[2 * (i * m + n) + 0] = in[n][2 * i + 0];
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out[2 * (i * m + n) + 1] = in[n][2 * i + 1];
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}
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}
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}
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size_t Synthesis::inputLen() const
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{
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return blockLen;
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}
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size_t Synthesis::outputLen() const
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{
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return blockLen * m;
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}
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float *Synthesis::inputBuffer(size_t chan) const
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{
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if (chan >= m)
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return NULL;
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return hOutputs[chan];
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}
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bool Synthesis::resetBuffer(size_t chan)
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{
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if (chan >= m)
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return false;
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memset(hOutputs[chan], 0, blockLen * 2 * sizeof(float));
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return true;
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}
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/*
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* Implementation based on material found in:
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*
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* "harris, fred, Multirate Signal Processing, Upper Saddle River, NJ,
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* Prentice Hall, 2006."
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*/
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bool Synthesis::rotate(float *out, size_t len)
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{
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size_t hSize = 2 * hLen * sizeof(float);
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if (!checkLen(blockLen, len)) {
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std::cout << "Length fail" << std::endl;
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exit(1);
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return false;
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}
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cxvec_fft(fftHandle);
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/*
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* Convolve through filterbank while applying and saving sample history
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*/
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for (size_t i = 0; i < m; i++) {
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memcpy(&hInputs[i][2 * -hLen], hist[i], hSize);
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memcpy(hist[i], &hInputs[i][2 * (blockLen - hLen)], hSize);
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convolve_real(hInputs[i], blockLen,
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subFilters[i], hLen,
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hOutputs[i], blockLen,
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0, blockLen);
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}
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/* Interleave into output vector */
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interleave(hOutputs, blockLen, out, m);
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return true;
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}
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Synthesis::Synthesis(size_t m, size_t blockLen, size_t hLen)
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: ChannelizerBase(m, blockLen, hLen)
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{
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}
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Synthesis::~Synthesis()
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{
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}
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