TwinRX: Remove decimation from frontend

The decimation in the rx_frontend_gen3 was added to reduce the bandwidth
between the Radio and the DDC due to the limitation in bandwidth over
the crossbar for dynamically connected blocks.  The default FPGA image
for the X300 now has a static connection between the Radio and DDC, so
this is no longer necessary.

This change allows the TwinRX receive channels to be time aligned with
channels from other daughterboards so they can be used in the same
streamer.

Signed-off-by: Michael West <michael.west@ettus.com>

1 files changed, 6 insertions, 18 deletions

diff --git a/host/lib/usrp/cores/rx_frontend_core_3000.cpp b/host/lib/usrp/cores/rx_frontend_core_3000.cpp
index 1dc8be745..756f0995d 100644
--- a/host/lib/usrp/cores/rx_frontend_core_3000.cpp
+++ b/host/lib/usrp/cores/rx_frontend_core_3000.cpp
@@ -23,11 +23,11 @@ using namespace uhd;
 #define REG_RX_FE_MAPPING (base + reg_offset * 4)
 #define REG_RX_FE_HET_CORDIC_PHASE (base + reg_offset * 5)
 
-#define FLAG_DSP_RX_MAPPING_SWAP_IQ (1 << 0)
-#define FLAG_DSP_RX_MAPPING_REAL_MODE (1 << 1)
-#define FLAG_DSP_RX_MAPPING_INVERT_Q (1 << 2)
-#define FLAG_DSP_RX_MAPPING_INVERT_I (1 << 3)
-#define FLAG_DSP_RX_MAPPING_REAL_DECIM (1 << 4)
+#define FLAG_DSP_RX_MAPPING_SWAP_IQ     (1 << 0)
+#define FLAG_DSP_RX_MAPPING_REAL_MODE   (1 << 1)
+#define FLAG_DSP_RX_MAPPING_INVERT_Q    (1 << 2)
+#define FLAG_DSP_RX_MAPPING_INVERT_I    (1 << 3)
+#define FLAG_DSP_RX_MAPPING_DOWNCONVERT (1 << 4)
 //#define FLAG_DSP_RX_MAPPING_RESERVED    (1 << 5)
 //#define FLAG_DSP_RX_MAPPING_RESERVED    (1 << 6)
 #define FLAG_DSP_RX_MAPPING_BYPASS_ALL (1 << 7)
@@ -102,7 +102,7 @@ public:
                 break;
             case fe_connection_t::HETERODYNE:
                 mapping_reg_val = FLAG_DSP_RX_MAPPING_REAL_MODE
-                                  | FLAG_DSP_RX_MAPPING_REAL_DECIM;
+                                  | FLAG_DSP_RX_MAPPING_DOWNCONVERT;
                 break;
             default:
                 mapping_reg_val = 0;
@@ -189,18 +189,6 @@ public:
                 &rx_frontend_core_3000::set_iq_balance, this, std::placeholders::_1));
     }
 
-    double get_output_rate()
-    {
-        switch (_fe_conn.get_sampling_mode()) {
-            case fe_connection_t::REAL:
-                return _adc_rate;
-            case fe_connection_t::HETERODYNE:
-                return _adc_rate / 2;
-            default:
-                return _adc_rate;
-        }
-    }
-
 private:
     int32_t _i_dc_off, _q_dc_off;
     double _adc_rate;