diff options
Diffstat (limited to 'Transceiver52M/USRPDevice.cpp')
| -rw-r--r-- | Transceiver52M/USRPDevice.cpp | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/Transceiver52M/USRPDevice.cpp b/Transceiver52M/USRPDevice.cpp index 5c99003..275f1c4 100644 --- a/Transceiver52M/USRPDevice.cpp +++ b/Transceiver52M/USRPDevice.cpp @@ -63,10 +63,25 @@ USRPDevice::USRPDevice(int sps, bool skipRx) : skipRx(skipRx) { LOG(INFO) << "creating USRP device..."; + + this->sps = sps; decimRate = (unsigned int) round(masterClockRate/((GSMRATE) * (double) sps)); actualSampleRate = masterClockRate/decimRate; rxGain = 0; + /* + * Undetermined delay b/w ping response timestamp and true + * receive timestamp. Values are empirically measured. With + * split sample rate Tx/Rx - 4/1 sps we need to need to + * compensate for advance rather than delay. + */ + if (sps == 1) + pingOffset = 272; + else if (sps == 4) + pingOffset = 269 - 7500; + else + pingOffset = 0; + #ifdef SWLOOPBACK samplePeriod = 1.0e6/actualSampleRate; loopbackBufferSize = 0; @@ -86,9 +101,10 @@ int USRPDevice::open(const std::string &) m_uRx.reset(); if (!skipRx) { try { - m_uRx = usrp_standard_rx_sptr(usrp_standard_rx::make(0,decimRate,1,-1, - usrp_standard_rx::FPGA_MODE_NORMAL, - 1024,16*8,rbf)); + m_uRx = usrp_standard_rx_sptr(usrp_standard_rx::make( + 0, decimRate * sps, 1, -1, + usrp_standard_rx::FPGA_MODE_NORMAL, + 1024, 16 * 8, rbf)); #ifdef HAVE_LIBUSRP_3_2 m_uRx->set_fpga_master_clock_freq(masterClockRate); #endif @@ -110,8 +126,9 @@ int USRPDevice::open(const std::string &) } try { - m_uTx = usrp_standard_tx_sptr(usrp_standard_tx::make(0,decimRate*2,1,-1, - 1024,16*8,rbf)); + m_uTx = usrp_standard_tx_sptr(usrp_standard_tx::make( + 0, decimRate * 2, 1, -1, + 1024, 16 * 8, rbf)); #ifdef HAVE_LIBUSRP_3_2 m_uTx->set_fpga_master_clock_freq(masterClockRate); #endif @@ -341,7 +358,7 @@ int USRPDevice::readSamples(short *buf, int len, bool *overrun, uint32_t word2 = usrp_to_host_u32(tmpBuf[2]); if ((word2 >> 16) == ((0x01 << 8) | 0x02)) { timestamp -= timestampOffset; - timestampOffset = pktTimestamp - pingTimestamp + PINGOFFSET; + timestampOffset = pktTimestamp - pingTimestamp + pingOffset; LOG(DEBUG) << "updating timestamp offset to: " << timestampOffset; timestamp += timestampOffset; isAligned = true; |