diff options
| -rw-r--r-- | host/lib/usrp/common/ad9361_driver/ad9361_device.cpp | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/host/lib/usrp/common/ad9361_driver/ad9361_device.cpp b/host/lib/usrp/common/ad9361_driver/ad9361_device.cpp index 5574022b6..6d687f80e 100644 --- a/host/lib/usrp/common/ad9361_driver/ad9361_device.cpp +++ b/host/lib/usrp/common/ad9361_driver/ad9361_device.cpp @@ -1242,7 +1242,11 @@ double ad9361_device_t::_tune_bbvco(const double rate) * (double)modulus); UHD_LOG_TRACE("AD936X", boost::format("[ad9361_device_t::_tune_bbvco] nint=%d nfrac=%d") % nint % nfrac); - double actual_vcorate = fref * ((double)nint + ((double)nfrac / (double)modulus)); + const double actual_vcorate = + fref * ((double)nint + ((double)nfrac / (double)modulus)); + UHD_LOG_TRACE("AD936X", + boost::format("[ad9361_device_t::_tune_bbvco] actual vcorate=%.10f") + % actual_vcorate); /* Scale CP current according to VCO rate */ const double icp_baseline = 150e-6; @@ -1507,8 +1511,14 @@ double ad9361_device_t::_setup_rates(const double rate) const double adcclk = _tune_bbvco(rate * divfactor); double dacclk = adcclk; - /* The DAC clock must be <= 336e6, and is either the ADC clock or 1/2 the - * ADC clock.*/ + // We keep the DAC clock <= 336 MHz, either the ADC clock or 1/2 the ADC + // clock. + // Note that current recommendations from ADI are 640 MHz for the ADC and + // 320 MHz for the DAC. We are thus overclocking the AD9361, since we are + // using these no longer valid recommendations, but they seem to work and we + // consider the risk of changing these higher than the benefit. We will add + // a log statement, though, so we can track back suboptimal RF performance + // to overclocked settings. if (adcclk > 336e6) { /* Make the DAC clock = ADC/2 */ _regs.bbpll = _regs.bbpll | 0x08; @@ -1516,6 +1526,16 @@ double ad9361_device_t::_setup_rates(const double rate) } else { _regs.bbpll = _regs.bbpll & 0xF7; } + if (dacclk > 320e6) { + UHD_LOG_DEBUG("AD936X", + "[ad9361_device_t::_setup_rates] DAC rate is overclocked! dacclk=" + << (dacclk / 1e6) << " MHz."); + } + if (dacclk > 640e6) { + UHD_LOG_DEBUG("AD936X", + "[ad9361_device_t::_setup_rates] ADC rate is overclocked! adcclk=" + << (adcclk / 1e6) << " MHz."); + } /* Set the dividers / interpolators in AD9361. */ _io_iface->poke8(0x002, _regs.txfilt); |