108 lines
2.4 KiB
C++
108 lines
2.4 KiB
C++
/*
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* Polyphase channelizer
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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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* 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 "Channelizer.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 deinterleave(const float *in, size_t ilen,
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float **out, size_t olen, size_t m)
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{
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size_t i, n;
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for (i = 0; i < olen; i++) {
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for (n = 0; n < m; n++) {
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out[m - 1 - n][2 * i + 0] = in[2 * (i * m + n) + 0];
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out[m - 1 - n][2 * i + 1] = in[2 * (i * m + n) + 1];
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}
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}
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}
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size_t Channelizer::inputLen() const
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{
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return blockLen * m;
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}
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size_t Channelizer::outputLen() const
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{
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return blockLen;
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}
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float *Channelizer::outputBuffer(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 hInputs[chan];
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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 Channelizer::rotate(const float *in, 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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return false;
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deinterleave(in, len, hInputs, blockLen, m);
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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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cxvec_fft(fftHandle);
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return true;
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}
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/* Setup channelizer paramaters */
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Channelizer::Channelizer(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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Channelizer::~Channelizer()
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{
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}
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