Trigger AC Description
Sequence: C37, ...
Trigger AC ( 10 KHz WBR for Ring-Plane Crossing )
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.
A very specific bitrate is targeted with this trigger, by specifying that the number of compressed
WBR data bytes be exactly 1150. Depending upon how well the Data Compression Chip is able to
compress the data, this will be expanded to perhaps 2K or 3K data samples. The intended bitrate
for the trigger is 75 kbps. It can be cut to a half or a fourth of this via a 73MEM_TWEAK command
following the trigger.
| Receiver |
Frequency Range |
Sensor |
Time between Snapshots |
Samples per Snapshot |
| WBR |
0 - 10 KHz |
EX |
0.125 second |
varies |
| 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), but its intended bitrate may vary.
In C37, this trigger was used to determine if the BX antenna might be used
by the WBR as a cyclic trigger for use during direction-finding modes. This
was done by "tweaking" the trigger AC setup with the BX-antenna command.