PDS_VERSION_ID         = PDS3                                                 
RECORD_TYPE            = STREAM                                               
OBJECT                 = TEXT                                                 
  PUBLICATION_DATE     = 2007-09-23                                           
  NOTE                 = "                                                    
      TRIG_A2.TXT describes the RPWS instrument configuration for the         
      Medium Frequency Receiver (MFR), the Wideband Reciever (WBR), the       
      Sounder, and the Dust detector algorithm when using Trigger A2."        
END_OBJECT           = TEXT                                                   
END                                                                           

Trigger A2 Description                                                        
                                                                              
Sequence:  C37, ...                                                           
Trigger A2 ( 10 KHz WBR Whistler)                                             
                                                                              
This trigger is designed to overlay 10-KHz Wideband Receiver data on top of   
a standard background trigger, such as 8A (Survey), 8E (night-time survey),   
or A0 (SEDDF).  Data acquisition continues for all receivers, with the        
exception of the dust detector and the sounder, which are disabled during     
this trigger's operation.  In addition, the MFR is switched to the EZ         
antenna to avoid interfering with the WBR, which is assumed to be connected   
to the EX antenna.  It is assumed that the WBR is pre-configured before this  
trigger is executed, except that the 10-KHz band selection is done by the     
trigger.  The standard setup done for the WBR by the background triggers is   
detailed below.  This trigger is similar to the cyclic Trigger 42, but it     
acquires larger buffers --- 3072 samples, with a duration of 110              
milliseconds.  This longer snapshot, schdeuled for every RTI, can provide     
nearly continuous coverage.  However, while the WBR is scheduled to acquire   
a 3072-sample snapshot every 1/8 second, in reality it is dependent on the    
telemetry mode and upon the amount of data compression achieved by the Data   
Compression Chip.  Typically the telemetry mode might be a 60 kbps data rate  
mode, resulting in something closer to 3/8 second between WBR snapshots.  If  
the telemetry mode supports a higher bitrate, then the nearly continuous      
coverage, intended to capture Whisltlers, is possible.                        
                                                                              
Receiver  Frequency Range  Sensor  Snapshot Spacing  Sample Size              
--------  ---------------  ------  ----------------  -----------              
WBR       0 - 10 KHz       EX      0.125 second      3072                     
MFR       25 - 12 KHz      EZ, BZ  32 seconds                                 
                                                                              
                                                                              
                                                                              
Other notes:                                                                  
                                                                              
There is a 60-second delay following the execution of this trigger, and       
preceding the start of the WBR data acquisition.  This allows time for the    
MFR to switch antennas and the sounder to finish any pending operation.       
                                                                              
This trigger will work with most non-direction-finding triggers, such as      
Trigger 28 (Interplanetary Cruise).