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| author | Josh Blum <josh@joshknows.com> | 2012-10-05 12:15:37 -0700 |
|---|---|---|
| committer | Josh Blum <josh@joshknows.com> | 2012-10-05 12:59:11 -0700 |
| commit | 3673ffd0921a3b6bf2cc9985ead0e337c001baf3 (patch) | |
| tree | a72f8e953f6b2ee9e0d29631ae1da7db19d3e10f | |
| parent | f969650555e1fbf87548d861e6b5126e8a641b3e (diff) | |
| download | uhd-3673ffd0921a3b6bf2cc9985ead0e337c001baf3.tar.gz uhd-3673ffd0921a3b6bf2cc9985ead0e337c001baf3.tar.bz2 uhd-3673ffd0921a3b6bf2cc9985ead0e337c001baf3.zip | |
usrp: ensure that actual_scalar does not rollover
For certain decimations/interpolations,
the scale factor adjustment may be greater than 1.0.
The > 1.0 factor needs to be adjusted out in the host.
| -rw-r--r-- | host/lib/usrp/cores/rx_dsp_core_200.cpp | 5 | ||||
| -rw-r--r-- | host/lib/usrp/cores/tx_dsp_core_200.cpp | 5 |
2 files changed, 6 insertions, 4 deletions
diff --git a/host/lib/usrp/cores/rx_dsp_core_200.cpp b/host/lib/usrp/cores/rx_dsp_core_200.cpp index a9b7d8672..b73baa81e 100644 --- a/host/lib/usrp/cores/rx_dsp_core_200.cpp +++ b/host/lib/usrp/cores/rx_dsp_core_200.cpp @@ -184,9 +184,10 @@ public: } void update_scalar(void){ - const double target_scalar = (1 << 17)*_scaling_adjustment/_dsp_extra_scaling; + const double factor = 1.0 + std::max(ceil_log2(_scaling_adjustment), 0.0); + const double target_scalar = (1 << 17)*_scaling_adjustment/_dsp_extra_scaling/factor; const boost::int32_t actual_scalar = boost::math::iround(target_scalar); - _fxpt_scalar_correction = target_scalar/actual_scalar; //should be small + _fxpt_scalar_correction = target_scalar/actual_scalar*factor; //should be small _iface->poke32(REG_DSP_RX_SCALE_IQ, actual_scalar); } diff --git a/host/lib/usrp/cores/tx_dsp_core_200.cpp b/host/lib/usrp/cores/tx_dsp_core_200.cpp index 2faf7c28b..f905a7551 100644 --- a/host/lib/usrp/cores/tx_dsp_core_200.cpp +++ b/host/lib/usrp/cores/tx_dsp_core_200.cpp @@ -136,9 +136,10 @@ public: } void update_scalar(void){ - const double target_scalar = (1 << 17)*_scaling_adjustment/_dsp_extra_scaling; + const double factor = 1.0 + std::max(ceil_log2(_scaling_adjustment), 0.0); + const double target_scalar = (1 << 17)*_scaling_adjustment/_dsp_extra_scaling/factor; const boost::int32_t actual_scalar = boost::math::iround(target_scalar); - _fxpt_scalar_correction = target_scalar/actual_scalar; //should be small + _fxpt_scalar_correction = target_scalar/actual_scalar*factor; //should be small _iface->poke32(REG_DSP_TX_SCALE_IQ, actual_scalar); } |