Trigger A8 Description

Sequence: C35
Trigger A8 ( RNGSAT, Rings & Satellite Regions )
This mode assumes a background survey mode, such as 8A or A0, is running, and on top of that 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 target bit rate is 5800 bps. During C35, in a short test, the measured bit rate was 5700 bps; this was using trigger 8A as the background trigger.

Receiver Frequency Range Sensors Time between Snapshots
MFR 25 - 12 KHz EX, 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 16 seconds
LP N/A Langmuir Probe 640 seconds
Sounder 3.6 - 115 KHz EX, EW 600 seconds



The HFR is in a modified "Composite Survey" mode, which now includes both auto- and cross-correlations for H1. 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        16       n    1000      1                3.6-319 kHz
H1   2E   y         y         2       n    80        1     60    25   325k-1.8MHz
H2   1E   n         n         1       n    20        1     72    200  1.8M-16MHz
Bands ABC require 3.16 sec to complete, H1 requires 5.47 sec, and H2 requires 1.46 sec for a total of 10.09 sec per sweep. However, the time between analyses is set to 16 seconds to reduce the bit rate. Every 600 seconds the HFR normal analyses are interrupted by a Sounder analysis. The Sounder operation has a duration of approximately 40 seconds. This Sounder analysis is defined by:
  sounder mode:   EZ AAA
  1st  sounder freq:      0
  last sounder freq:     89
  T1 delay:        10 msec
  T2 delay:        25 msec
  T3 delay:        25 msec
  passive spectra:      2
  active  spectra:      2
  # of cycles:       1
  sounder output A:      3 autos
  sounder output B:      3  AGCs