| /* |
| * Radio device interface with sample rate conversion |
| * |
| * Copyright (C) 2011-2014 Free Software Foundation, Inc. |
| * Copyright (C) 2015 Ettus Research LLC |
| * |
| * Author: Tom Tsou <tom@tsou.cc> |
| * |
| * 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 <radioInterface.h> |
| #include <Logger.h> |
| |
| #include "Resampler.h" |
| |
| extern "C" { |
| #include "convert.h" |
| } |
| |
| /* Resampling parameters for 64 MHz clocking */ |
| #define RESAMP_64M_INRATE 65 |
| #define RESAMP_64M_OUTRATE 96 |
| |
| /* Resampling parameters for 100 MHz clocking */ |
| #define RESAMP_100M_INRATE 52 |
| #define RESAMP_100M_OUTRATE 75 |
| |
| /* Universal resampling parameters */ |
| #define NUMCHUNKS 24 |
| |
| /* |
| * Resampling filter bandwidth scaling factor |
| * This narrows the filter cutoff relative to the output bandwidth |
| * of the polyphase resampler. At 4 samples-per-symbol using the |
| * 2 pulse Laurent GMSK approximation gives us below 0.5 degrees |
| * RMS phase error at the resampler output. |
| */ |
| #define RESAMP_TX4_FILTER 0.45 |
| |
| static Resampler *upsampler = NULL; |
| static Resampler *dnsampler = NULL; |
| static size_t resamp_inrate = 0; |
| static size_t resamp_inchunk = 0; |
| static size_t resamp_outrate = 0; |
| static size_t resamp_outchunk = 0; |
| |
| RadioInterfaceResamp::RadioInterfaceResamp(RadioDevice *wRadio, |
| size_t tx_sps, size_t rx_sps) |
| : RadioInterface(wRadio, tx_sps, rx_sps, 1), |
| outerSendBuffer(NULL), outerRecvBuffer(NULL) |
| { |
| } |
| |
| RadioInterfaceResamp::~RadioInterfaceResamp() |
| { |
| close(); |
| } |
| |
| void RadioInterfaceResamp::close() |
| { |
| delete outerSendBuffer; |
| delete outerRecvBuffer; |
| |
| delete upsampler; |
| delete dnsampler; |
| |
| outerSendBuffer = NULL; |
| outerRecvBuffer = NULL; |
| |
| upsampler = NULL; |
| dnsampler = NULL; |
| |
| if (sendBuffer.size()) |
| sendBuffer[0] = NULL; |
| if (recvBuffer.size()) |
| recvBuffer[0] = NULL; |
| |
| RadioInterface::close(); |
| } |
| |
| /* Initialize I/O specific objects */ |
| bool RadioInterfaceResamp::init(int type) |
| { |
| float cutoff = 1.0f; |
| |
| close(); |
| |
| sendBuffer.resize(1); |
| recvBuffer.resize(1); |
| convertSendBuffer.resize(1); |
| convertRecvBuffer.resize(1); |
| mReceiveFIFO.resize(1); |
| powerScaling.resize(1); |
| |
| switch (type) { |
| case RadioDevice::RESAMP_64M: |
| resamp_inrate = RESAMP_64M_INRATE; |
| resamp_outrate = RESAMP_64M_OUTRATE; |
| break; |
| case RadioDevice::RESAMP_100M: |
| resamp_inrate = RESAMP_100M_INRATE; |
| resamp_outrate = RESAMP_100M_OUTRATE; |
| break; |
| case RadioDevice::NORMAL: |
| default: |
| LOG(ALERT) << "Invalid device configuration"; |
| return false; |
| } |
| |
| resamp_inchunk = resamp_inrate * 4 * mSPSRx; |
| resamp_outchunk = resamp_outrate * 4 * mSPSRx; |
| |
| if (mSPSTx == 4) |
| cutoff = RESAMP_TX4_FILTER; |
| |
| dnsampler = new Resampler(resamp_inrate, resamp_outrate); |
| if (!dnsampler->init()) { |
| LOG(ALERT) << "Rx resampler failed to initialize"; |
| return false; |
| } |
| |
| upsampler = new Resampler(resamp_outrate, resamp_inrate); |
| if (!upsampler->init(cutoff)) { |
| LOG(ALERT) << "Tx resampler failed to initialize"; |
| return false; |
| } |
| |
| /* |
| * Allocate high and low rate buffers. The high rate receive |
| * buffer and low rate transmit vectors feed into the resampler |
| * and requires headroom equivalent to the filter length. Low |
| * rate buffers are allocated in the main radio interface code. |
| */ |
| sendBuffer[0] = new RadioBuffer(NUMCHUNKS, resamp_inchunk, |
| upsampler->len(), true); |
| recvBuffer[0] = new RadioBuffer(NUMCHUNKS * 20, resamp_inchunk, 0, false); |
| |
| outerSendBuffer = |
| new signalVector(NUMCHUNKS * resamp_outchunk); |
| outerRecvBuffer = |
| new signalVector(resamp_outchunk, dnsampler->len()); |
| |
| convertSendBuffer[0] = new short[outerSendBuffer->size() * 2]; |
| convertRecvBuffer[0] = new short[outerRecvBuffer->size() * 2]; |
| |
| return true; |
| } |
| |
| /* Receive a timestamped chunk from the device */ |
| void RadioInterfaceResamp::pullBuffer() |
| { |
| bool local_underrun; |
| int rc, num_recv; |
| |
| if (recvBuffer[0]->getFreeSegments() <= 0) |
| return; |
| |
| /* Outer buffer access size is fixed */ |
| num_recv = mRadio->readSamples(convertRecvBuffer, |
| resamp_outchunk, |
| &overrun, |
| readTimestamp, |
| &local_underrun); |
| if (num_recv != (int) resamp_outchunk) { |
| LOG(ALERT) << "Receive error " << num_recv; |
| return; |
| } |
| |
| convert_short_float((float *) outerRecvBuffer->begin(), |
| convertRecvBuffer[0], 2 * resamp_outchunk); |
| |
| underrun |= local_underrun; |
| readTimestamp += (TIMESTAMP) resamp_outchunk; |
| |
| /* Write to the end of the inner receive buffer */ |
| rc = dnsampler->rotate((float *) outerRecvBuffer->begin(), |
| resamp_outchunk, |
| recvBuffer[0]->getWriteSegment(), |
| resamp_inchunk); |
| if (rc < 0) { |
| LOG(ALERT) << "Sample rate upsampling error"; |
| } |
| |
| /* Set history for the next chunk */ |
| outerRecvBuffer->updateHistory(); |
| } |
| |
| /* Send a timestamped chunk to the device */ |
| bool RadioInterfaceResamp::pushBuffer() |
| { |
| int rc; |
| size_t numSent; |
| |
| if (sendBuffer[0]->getAvailSegments() <= 0) |
| return false; |
| |
| /* Always send from the beginning of the buffer */ |
| rc = upsampler->rotate(sendBuffer[0]->getReadSegment(), |
| resamp_inchunk, |
| (float *) outerSendBuffer->begin(), |
| resamp_outchunk); |
| if (rc < 0) { |
| LOG(ALERT) << "Sample rate downsampling error"; |
| } |
| |
| convert_float_short(convertSendBuffer[0], |
| (float *) outerSendBuffer->begin(), |
| powerScaling[0], 2 * resamp_outchunk); |
| |
| numSent = mRadio->writeSamples(convertSendBuffer, |
| resamp_outchunk, |
| &underrun, |
| writeTimestamp); |
| if (numSent != resamp_outchunk) { |
| LOG(ALERT) << "Transmit error " << numSent; |
| } |
| |
| writeTimestamp += resamp_outchunk; |
| |
| return true; |
| } |