PDS_VERSION_ID         = PDS3                                                 
RECORD_TYPE            = STREAM                                               
OBJECT                 = TEXT                                                 
  PUBLICATION_DATE     = 2010-06-27                                           
  NOTE                 = "                                                    
      TRIG_66.TXT describes the RPWS instrument configuration for the         
      High Frequency Receiver (HFR), the Medium Frequency Receiver            
      (MFR), the Waveform Receiver (WFR), the Wideband Reciever (WBR),        
      the Langmiur Probe (LP), the Sounder, and the Dust detector             
      algorithm when using Trigger 66."                                       
END_OBJECT           = TEXT                                                   
END                                                                           

Trigger 66 Description                                                        
                                                                              
Sequence:  S05, ...                                                           
Trigger 66 ( Titan Closest Approach with 80-KHz WBR)                          
This mode assumes a background survey mode, such as 8A or A0, is running,     
although the HFR settings are set for the "Inner Magnetosphere Night-Time"    
mode, with fast time constants, as in Triggers A0 or 8E.  The duty cycle of   
the Langmuir Probe and the WFR are increased, and 80-KHz WBR is added.        
                                                                              
First of all, Trigger 66 overlays fast WFR data acquisition.  In order to do  
this,the LFDR data acquisition is stopped (it can be synthesized on the       
ground, using the fast WFR data.) A WFR snapshot, in its nominal 5-channel    
and 2048-sample mode, is acquired every 24 seconds.  The WFR is run in        
toggle mode, so these snapshots alternate between 25 Hz mode and 2.5 KHz      
mode.  In addition to stopping the LFDR data acquisition, the data            
compression algorithm for the WFR is changed to "packed" mode, so that this   
faster data rate can be accomplished.  The 80-KHz WBR is added, using the EX  
antenna, but the sample size is limited to 1536 compressed bytes in order to  
accomplish a particular bitrate.  The target bit rate is 100 kbps.  Actual    
measured bitrates look like about 55.5 kbps for the S&ER-3 telemetry mode     
(maximum 60.928 kbps), and 103.6 kbps for higher pickup rates.  The former    
was measured in C37, the latter during C38.                                   
                                                                              
The Langmuir Probe sweep rate is increased to once every 24 seconds.  While   
a faster rate would be desirable, this would cause interference in the WFR    
data, also being acquired every 24 seconds.  Between each LP sweep, a         
432-point density mode measurement is made at 20 Hz.  Additionally, the       
Langmuir Probe sweep, a down-up ramp type of sweep, is done in Medium Range   
mode, so the voltage range is +4V to -4V.  The density measurement is done    
in fixed bias mode, at +4V.                                                   
                                                                              
Receiver  Frequency Range   Sensors         Snapshot Spacing                  
--------  ----------------  --------------  ----------------                  
MFR       25 - 12 KHz       EZ, BZ          32 seconds                        
WFR       1 - 25 Hz         EX,EW,BX,BY,BZ  48 seconds                        
WFR       .1 - 2.5 KHz      EX,EW,BX,BY,BZ  48 seconds                        
HFR       3.6 KHz - 16 MHz  EX, EW          8 or 16 seconds                   
LP        N/A               Langmuir Probe  24 seconds                        
WBR       0 - 80 KHz        EX              0.125 second                      
                                                                              
                                                                              
                                                                              
The HFR is in the newest version of "Nighttime Survey" mode, which now        
includes both auto- and cross-correlations for H1, and modified integration   
constants for all bands.  This mode is defined by:                            
                                                                              
                                                                              
          Correlations Channels    Integ.           Size Frequency            
Band Ant. Auto- Cross- per Band df Period Rep Steps kHz  Start - Stop         
---- ---- ----- ------ -------- -- ------ --- ----- ---- ------------         
ABC   2E    y     y       32    n    500  1              3.6-319KHz           
HF1   2E    y     y        2    n     40  1     60    25 0.325-1.825MHz       
HF2   1E    n     n        1    n     40  1     72   200 1.825-16.225MHz      
                                                                              
Bands ABC require 1.580 sec to complete, H1 requires 2.852 sec, and           
H2 requires 2.534 sec for a total of 6.966 sec per sweep.  The hfr            
cycle time is 8.000 seconds.                                                  
                                                                              
                                                                              
                                                                              
No Sounder measurements are made in this mode.  No onboard dust detection is  
done either.