diff --git a/applications/lofar2/doc/prestudy/station2_sdp_icd.txt b/applications/lofar2/doc/prestudy/station2_sdp_icd.txt
index 96c60c81f16a140e6ac03fa9d0d60387014c4851..5664d46548ab200ce63c8985bad70fbb013624f8 100755
--- a/applications/lofar2/doc/prestudy/station2_sdp_icd.txt
+++ b/applications/lofar2/doc/prestudy/station2_sdp_icd.txt
@@ -310,18 +310,19 @@ The total number of streams to CEP then becomes NOF_BEAMSETS * NOF_LANES.
     . the frequency_band: 0 = 10-90, 1 = 30-90, 2 = 110-190, 3 = 170-230, 4 = 210-240, 5 = 210-250 MHz,
       because these may differ per RCU2 (= RCU modes)
     . the Nyquist zone information, because that is an implementation detail that is redundant with the
-      frequency_band information
+      frequency_band information, however it is available because it is used to set spectral inversion.
     . the number nof antenna in array, because that that depends on the beam control which may differ per
       beamlet.
     Try use same fields as for statistics
       
-  . 1b antenna_band: 0 = LBAS, 1 = HBAS [LOFAR2-3098, 6996]
+  . 1b antenna_band: 0 = LB, 1 = HB [LOFAR2-3098, 6996]
+  . 2b nyquist_zone_index: Nyquist sampling zone index, 0 for LB, 1 or 2 for HB, 0 = first zone from 0-f_adc/2 Hz, 1 = second zone from f_adc/2:f_adc Hz, 2 = third zone from f_adc-f_adc*3/2 Hz
   . 1b f_adc, sample clock frequency of the ADC, 0 = 160 MHz, 1 = 200 MHz [LOFAR2-3578]
   . 1b fsub_type: 0 = critically sampled PFB , 1 = oversampled PFB [LOFAR2-2278]
        - rather than transporting p, q for R_os = p/q
        - the f_adc and fsub_type are in the header, because this information is sufficent to know the subband
          frequency grid (f_sub = f_adc / N_fft = 195312.5 or 156250 Hz) and the subband sample rate (R_os * f_sub).
-  . 1b data_flag: 0 = data ok, 1 = data disturbed, due to repositioning of beam [LOFAR2-3123]
+  . 1b data_flag: 0 = beamlet data ok, 1 = beamlet data disturbed, due to repositioning of beam [LOFAR2-3123]
     1b payload_error, 0 = payload data is ok, 1 one or more blocks in payload have data errors, indicating
        some problem at Station (purpose: fault analysis)
        - a single payload error bit means that all blocks in the payload get discarded if only only block
@@ -366,6 +367,7 @@ The total number of streams to CEP then becomes NOF_BEAMSETS * NOF_LANES.
         beamlet_scale = 256     * norm -->    64
       After mutliplying the 18b.0b beamlet_sum by 1b.12b 1/beamlet_scale the result is a 24b.12b value that is rounded and 
       clipped to output the 8b beamlets.
+      
         
 
 - 1 Byte, reserved (= 0)