Use LOFAR PFIR coefficients that have no DC.

applications/apertif/designs/apertif_unb1_bn_filterbank/src/vhdl/apertif_unb1_bn_filterbank.vhd

@@ -120,9 +120,10 @@ ARCHITECTURE str OF apertif_unb1_bn_filterbank IS
 
   CONSTANT c_pps_delay_max            : NATURAL := 2**12 - 1;  -- 4095 * 5 ns ~= 20000 ns ~= 6 km @ speed of light in air
 
-    -- Wideband Poly Phase Filter Bank                
-  CONSTANT c_wpfb_coefs_file_prefix   : STRING := "hex/coefs_wide";          -- use same PFIR coefficients as in LOFAR
-  --CONSTANT c_wpfb_coefs_file_prefix   : STRING := "hex/coefs_nodc_wide";   -- use LOFAR PFIR coefficients that have no DC
+  -- Wideband Poly Phase Filter Bank
+  -- Use $RADIOHDL/libraries/dsp/filter/src/python/diff_lofar_coefs to verify that the correct PFIR coefficients are used.
+  --CONSTANT c_wpfb_coefs_file_prefix   : STRING := "hex/coefs_wide";          -- use same PFIR coefficients as in LOFAR
+  CONSTANT c_wpfb_coefs_file_prefix   : STRING := "hex/coefs_nodc_wide";   -- use LOFAR PFIR coefficients that have no DC
 
   CONSTANT c_ram_st_sst_adr_w         : NATURAL := 12; 
   CONSTANT c_ram_fil_coefs_adr_w      : NATURAL := 15;