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