Trigger A6 Description

Sequence: C37
Trigger A6 ( MAG BOUNDARY(max) )
This mode assumes a background survey mode, such as 8A or 8E, is running, and on top of that overlays fast WFR data acquisition. In order to do this, the LFR data acquisition is changed from its default of toggle mode to Hiband-only. This provides the MFR-2 replacement data. The WFR is run in LoBand-only mode. The 1-10Hz LFR data 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, giving almost continuous coverage. In addition to limiting the LFR 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 6000 bps. During C37, in a short test, the measured bit rate was 5500 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
MFDR	200 - 1400 Hz	EX, BX	60 seconds
WFR	1 - 25 Hz	EX,EW,BX,BY,BZ	24 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       32    n   1000  1              3.6-319KHz
HF1   2E    y     y        2    n     80  1     60    25 0.325-1.825MHz
HF2   1E    n     n        1    n     40  1    143   100 1.825-16.125MHz

Bands ABC require 3.120 sec to complete, H1 requires 5.473 sec, and
H2 requires 5.034 sec for a total of 13.626 sec per sweep.  The hfr
cycle time is 16.000 seconds.

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: Ex AAA
1st  Sounder Frequency:   0
last Sounder Frequency:  89
T1 delay:   5 milliseconds
T2 delay:   5 milliseconds
T3 delay:  15 milliseconds
Passive Spectra:   2
Active  Spectra:   2
No. of Cycles:     1
Sounder Output A:   3 Autos
Sounder Output B:   3 AGCs