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 |
Time between Snapshots |
Samples per Snapshot |
| 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).