Use local input ref_sync for BSN monitor of beamlet output.

applications/lofar2/libraries/sdp/src/vhdl/node_sdp_beamformer.vhd

@@ -132,11 +132,14 @@ ARCHITECTURE str OF node_sdp_beamformer IS
   SIGNAL scope_bf_out_sosi_arr   : t_dp_sosi_integer_arr(c_sdp_N_pol_bf-1 DOWNTO 0);
   SIGNAL beamlet_scale           : STD_LOGIC_VECTOR(c_sdp_W_beamlet_scale-1 DOWNTO 0);
   
-  SIGNAL rn_index              : NATURAL RANGE 0 TO c_sdp_N_pn_max-1 := 0;
+  SIGNAL rn_index                : NATURAL RANGE 0 TO c_sdp_N_pn_max-1 := 0;
+  SIGNAL ref_sync                : STD_LOGIC;
 
 BEGIN
 
-  rn_index <= TO_UINT(SUB_UVEC(gn_id, ring_info.O_rn)) WHEN rising_edge(dp_clk); -- Using register to ease timing closure.
+  -- Use register to ease timing closure.
+  rn_index <= TO_UINT(SUB_UVEC(gn_id, ring_info.O_rn)) WHEN rising_edge(dp_clk);
+  ref_sync <= in_sosi_arr(0).sync WHEN rising_edge(dp_clk);
 
   ---------------------------------------------------------------
   -- Beamlet Subband Select 
@@ -297,7 +300,7 @@ BEGIN
     -- Streaming clock domain
     dp_rst         => dp_rst,
     dp_clk         => dp_clk,
-    ref_sync       => mon_bf_udp_sosi.sync, 
+    ref_sync       => ref_sync,
 
     in_sosi_arr(0) => mon_bf_udp_sosi
   );