From 3673ffd0921a3b6bf2cc9985ead0e337c001baf3 Mon Sep 17 00:00:00 2001 From: Josh Blum Date: Fri, 5 Oct 2012 12:15:37 -0700 Subject: 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. --- host/lib/usrp/cores/rx_dsp_core_200.cpp | 5 +++-- host/lib/usrp/cores/tx_dsp_core_200.cpp | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) (limited to 'host/lib/usrp') 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); } -- cgit v1.2.3