iq_txshift must be 4 since Iris expects the samples to be on the 12-bit msb

targets/ARCH/IRIS/USERSPACE/LIB/iris_lib.cpp

@@ -468,7 +468,7 @@ extern "C" {
 		break;
 	}
 
-        openair0_cfg[0].iq_txshift = 0;//shift
+        openair0_cfg[0].iq_txshift = 4;//shift
 
 	for(i=0; i < s->iris->getNumChannels(SOAPY_SDR_RX); i++) {
 		if (i < openair0_cfg[0].rx_num_channels) {

targets/PROJECTS/GENERIC-LTE-EPC/CONF/enb.band7.tm1.iris030.conf

@@ -153,7 +153,7 @@ rrh_gw_config = ({
     rrh_gw_active = "yes";
     tr_preference = "raw";
     rf_preference = "iris030";
-    iq_txshift = 0;
+    iq_txshift = 4;
     tx_sample_advance = 60;	
     tx_scheduling_advance = 9;