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transceiver: add option for host based resampling

The resampling transceiver is unified with the 52MHz
version. The option to resample 400ksps from the device
to a GSM appropriate 270.833ksps is enabled at compile
time with the following option.

   ./configure --with-resamp

Signed-off-by: Thomas Tsou <ttsou@vt.edu>
master
Thomas Tsou 11 years ago
parent b667ea6267
commit bb1c2f2ad2
  1. 16
      public-trunk/Transceiver52M/UHDDevice.cpp
  2. 316
      public-trunk/Transceiver52M/radioIOResamp.cpp

@ -26,10 +26,15 @@
#include <uhd/utils/thread_priority.hpp>
#include <uhd/utils/msg.hpp>
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
/*
use_ext_ref - Enable external 10MHz clock reference
master_clk_rt - Master clock frequency
master_clk_rt - Master clock frequency - ignored if host resampling is
enabled
rx_smpl_offset - Timing correction in seconds between receive and
transmit timestamps. This value corrects for delays on
@ -42,10 +47,15 @@
*/
const bool use_ext_ref = false;
const double master_clk_rt = 52e6;
const double rx_smpl_offset = .0000869;
const size_t smpl_buf_sz = (1 << 20);
const float tx_ampl = .3;
#ifdef RESAMPLE
const double rx_smpl_offset = .00005;
#else
const double rx_smpl_offset = .0000869;
#endif
/** Timestamp conversion
@param timestamp a UHD or OpenBTS timestamp
@param rate sample rate
@ -313,6 +323,7 @@ double uhd_device::set_rates(double rate)
{
double actual_rt, actual_clk_rt;
#ifndef RESAMPLE
// Set master clock rate
usrp_dev->set_master_clock_rate(master_clk_rt);
actual_clk_rt = usrp_dev->get_master_clock_rate();
@ -321,6 +332,7 @@ double uhd_device::set_rates(double rate)
LOG(ERROR) << "Failed to set master clock rate";
return -1.0;
}
#endif
// Set sample rates
usrp_dev->set_tx_rate(rate);

@ -0,0 +1,316 @@
/*
* Radio device interface with sample rate conversion
* Written by Thomas Tsou <ttsou@vt.edu>
*
* Copyright 2011 Free Software Foundation, Inc.
*
* 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>
/* New chunk sizes for resampled rate */
#ifdef INCHUNK
#undef INCHUNK
#endif
#ifdef OUTCHUNK
#undef OUTCHUNK
#endif
/* Resampling parameters */
#define INRATE 65 * SAMPSPERSYM
#define INHISTORY INRATE * 2
#define INCHUNK INRATE * 9
#define OUTRATE 96 * SAMPSPERSYM
#define OUTHISTORY OUTRATE * 2
#define OUTCHUNK OUTRATE * 9
/* Resampler low pass filters */
signalVector *tx_lpf = 0;
signalVector *rx_lpf = 0;
/* Resampler history */
signalVector *tx_hist = 0;
signalVector *rx_hist = 0;
/* Resampler input buffer */
signalVector *tx_vec = 0;
signalVector *rx_vec = 0;
/* High rate (device facing) buffers */
short tx_buf[INCHUNK * 2 * 2];
short rx_buf[OUTCHUNK * 2 * 2];
/*
* Utilities and Conversions
*
* Manipulate signal vectors dynamically for two reasons. For one,
* it's simpler. And two, it doesn't make any reasonable difference
* relative to the high overhead generated by the resampling.
*/
/* Concatenate signal vectors. Deallocate input vectors. */
signalVector *concat(signalVector *a, signalVector *b)
{
signalVector *vec = new signalVector(*a, *b);
delete a;
delete b;
return vec;
}
/* Segment a signal vector. Deallocate the input vector. */
signalVector *segment(signalVector *a, int indx, int sz)
{
signalVector *vec = new signalVector(sz);
a->segmentCopyTo(*vec, indx, sz);
delete a;
return vec;
}
/* Create a new signal vector from a short array. */
signalVector *short_to_sigvec(short *smpls, size_t sz)
{
int i;
signalVector *vec = new signalVector(sz);
signalVector::iterator itr = vec->begin();
for (i = 0; i < sz; i++) {
*itr++ = Complex<float>(smpls[2 * i + 0], smpls[2 * i + 1]);
}
return vec;
}
/* Convert and deallocate a signal vector into a short array. */
int sigvec_to_short(signalVector *vec, short *smpls)
{
int i;
signalVector::iterator itr = vec->begin();
for (i = 0; i < vec->size(); i++) {
smpls[2 * i + 0] = itr->real();
smpls[2 * i + 1] = itr->imag();
itr++;
}
delete vec;
return i;
}
/* Create a new signal vector from a float array. */
signalVector *float_to_sigvec(float *smpls, int sz)
{
int i;
signalVector *vec = new signalVector(sz);
signalVector::iterator itr = vec->begin();
for (i = 0; i < sz; i++) {
*itr++ = Complex<float>(smpls[2 * i + 0], smpls[2 * i + 1]);
}
return vec;
}
/* Convert and deallocate a signal vector into a float array. */
int sigvec_to_float(signalVector *vec, float *smpls)
{
int i;
signalVector::iterator itr = vec->begin();
for (i = 0; i < vec->size(); i++) {
smpls[2 * i + 0] = itr->real();
smpls[2 * i + 1] = itr->imag();
itr++;
}
delete vec;
return i;
}
/* Initialize resampling signal vectors */
void init_resampler(signalVector **lpf,
signalVector **buf,
signalVector **hist,
int tx)
{
int P, Q, taps, hist_len;
float cutoff_freq;
if (tx) {
LOG(INFO) << "Initializing Tx resampler";
P = OUTRATE;
Q = INRATE;
taps = 651;
hist_len = INHISTORY;
} else {
LOG(INFO) << "Initializing Rx resampler";
P = INRATE;
Q = OUTRATE;
taps = 961;
hist_len = OUTHISTORY;
}
if (!*lpf) {
cutoff_freq = (P < Q) ? (1.0/(float) Q) : (1.0/(float) P);
*lpf = createLPF(cutoff_freq, taps, P);
}
if (!*buf) {
*buf = new signalVector();
}
if (!*hist);
*hist = new signalVector(hist_len);
}
/* Resample a signal vector
*
* The input vector is deallocated and the pointer returned with a vector
* of any unconverted samples.
*/
signalVector *resmpl_sigvec(signalVector *hist, signalVector **vec,
signalVector *lpf, double in_rate,
double out_rate, int chunk_sz)
{
signalVector *resamp_vec;
int num_chunks = (*vec)->size() / chunk_sz;
/* Truncate to a chunk multiple */
signalVector trunc_vec(num_chunks * chunk_sz);
(*vec)->segmentCopyTo(trunc_vec, 0, num_chunks * chunk_sz);
/* Update sample buffer with remainder */
*vec = segment(*vec, trunc_vec.size(), (*vec)->size() - trunc_vec.size());
/* Add history and resample */
signalVector input_vec(*hist, trunc_vec);
resamp_vec = polyphaseResampleVector(input_vec, in_rate,
out_rate, lpf);
/* Update history */
trunc_vec.segmentCopyTo(*hist, trunc_vec.size() - hist->size(),
hist->size());
return resamp_vec;
}
/* Wrapper for receive-side integer-to-float array resampling */
int rx_resmpl_int_flt(float *smpls_out, short *smpls_in, int num_smpls)
{
int num_resmpld, num_chunks;
signalVector *convert_vec, *resamp_vec, *trunc_vec;
if (!rx_lpf || !rx_vec || !rx_hist)
init_resampler(&rx_lpf, &rx_vec, &rx_hist, false);
/* Convert and add samples to the receive buffer */
convert_vec = short_to_sigvec(smpls_in, num_smpls);
rx_vec = concat(rx_vec, convert_vec);
num_chunks = rx_vec->size() / OUTCHUNK;
if (num_chunks < 1)
return 0;
/* Resample */
resamp_vec = resmpl_sigvec(rx_hist, &rx_vec, rx_lpf,
INRATE, OUTRATE, OUTCHUNK);
/* Truncate */
trunc_vec = segment(resamp_vec, INHISTORY,
resamp_vec->size() - INHISTORY);
/* Convert */
num_resmpld = sigvec_to_float(trunc_vec, smpls_out);
return num_resmpld;
}
/* Wrapper for transmit-side float-to-int array resampling */
int tx_resmpl_flt_int(short *smpls_out, float *smpls_in, int num_smpls)
{
int num_resmpl, num_chunks;
signalVector *convert_vec, *resamp_vec;
if (!tx_lpf || !tx_vec || !tx_hist)
init_resampler(&tx_lpf, &tx_vec, &tx_hist, true);
/* Convert and add samples to the transmit buffer */
convert_vec = float_to_sigvec(smpls_in, num_smpls);
tx_vec = concat(tx_vec, convert_vec);
num_chunks = tx_vec->size() / INCHUNK;
if (num_chunks < 1)
return 0;
/* Resample and convert to an integer array */
resamp_vec = resmpl_sigvec(tx_hist, &tx_vec, tx_lpf,
OUTRATE, INRATE, INCHUNK);
num_resmpl = sigvec_to_short(resamp_vec, smpls_out);
return num_resmpl;
}
/* Receive a timestamped chunk from the device */
void RadioInterface::pullBuffer()
{
int num_cv, num_rd;
bool local_underrun;
/* Read samples. Fail if we don't get what we want. */
num_rd = mRadio->readSamples(rx_buf, OUTCHUNK, &overrun,
readTimestamp, &local_underrun);
LOG(DEEPDEBUG) << "Rx read " << num_rd << " samples from device";
assert(num_rd == OUTCHUNK);
underrun |= local_underrun;
readTimestamp += (TIMESTAMP) num_rd;
/* Convert and resample */
num_cv = rx_resmpl_int_flt(rcvBuffer + 2 * rcvCursor,
rx_buf, num_rd);
LOG(DEEPDEBUG) << "Rx read " << num_cv << " samples from resampler";
rcvCursor += num_cv;
}
/* Send a timestamped chunk to the device */
void RadioInterface::pushBuffer()
{
int num_cv, num_wr;
if (sendCursor < INCHUNK)
return;
LOG(DEEPDEBUG) << "Tx wrote " << sendCursor << " samples to resampler";
/* Resample and convert */
num_cv = tx_resmpl_flt_int(tx_buf, sendBuffer, sendCursor);
assert(num_cv > sendCursor);
/* Write samples. Fail if we don't get what we want. */
num_wr = mRadio->writeSamples(tx_buf + OUTHISTORY * 2,
num_cv - OUTHISTORY,
&underrun,
writeTimestamp);
LOG(DEEPDEBUG) << "Tx wrote " << num_wr << " samples to device";
assert(num_wr == num_wr);
writeTimestamp += (TIMESTAMP) num_wr;
sendCursor = 0;
}