Alarm Logic Overview

Alarm Criteria

Alarm Criteria are defined by Boolean expressions acting on information about a given pulse or pass and the microphone that recorded it. Pulses or passes that meet the criteria are then processed by the Pass Settings and Pulse Settings to determine if either the pass-level alarm or pulse-level alarm should be raised.

Pulse-Level Alarm Behavior

Pulse-level alarms operate on the measurements of each individual pulse recorded by the SMART System, without regard for how pulses are separated into passes based on each microphone's trigger settings.

Each pulse alarm has a Pulse Period, a rolling time window over which it counts the number of pulses that meet the Alarm Criteria. Pulse activity can be defined as the number of matching pulses within the trailing Pulse Period.

A pulse-level alarm follows this sequence:

1. If pulse activity exceeds the High Water Mark, the alarm is raised.
2. Once the alarm is raised, it will continue to stay raised while pulse activity remains above the High Water Mark.
3. How the alarm ends depends on whether a Pulse Alarm Hold is set:

   If no Pulse Alarm Hold is set, when pulse activity drops below the Low Water Mark, the alarm ends.

   If a Pulse Alarm Hold is set, the logic follows this sequence:

   1. When pulse activity drops to or below the Low Water Mark, the Pulse Alarm Hold period starts counting down.
   2. If pulse activity exceeds the High Water Mark again before the Pulse Alarm Hold period has elapsed, the alarm remains active and the Pulse Alarm Hold period resets to its full value.
   3. After pulse activity drops to or below the Low Water Mark and does not rise above the High Water Mark for the duration of the Pulse Alarm Hold period, the alarm ends.

Pass-Level Alarm Behavior

The pass-level alarm acts on the average measurements of multiple pulses, trigger-by-trigger. How many bat pulses constitute a single pass and how passes are separated from each other in time are determined using the trigger settings defined in a Setting Profile.

After each triggered recording, the SMART System calculates average (or cumulative, in the case of pulse count) call parameters for all of the pulses recorded during the trigger. These parameters are processed using the same Alarm Criteria as the pulse-level alarm. Match passes are then processed by the Pass Settings. Though the pulse-level alarm and pass-level alarm use the same Alarm Criteria, they can have different settings to determine how many positive matches are required to raise the alarm, and within what time period.

Pass activity can be defined as the number of passes that match the Alarm Criteria within the trailing Pass Period.

A pass-level alarm follows the same basic logic as pulse-level alarms:

1. If pass activity exceeds the High Water Mark, the alarm is raised.
2. Once the alarm is raised, it will continue to stay raised while pass activity remains above the High Water Mark.
3. How the alarm ends depends on whether a Pass Alarm Hold is set:

   If no Pass Alarm Hold is set, when pass activity drops below the Low Water Mark, the alarm ends.

   If a Pass Alarm Hold is set, the logic follows this sequence:

   1. When pass activity drops to or below the Low Water Mark, the Pass Alarm Hold period starts counting down.
   2. If pass activity exceeds the High Water Mark again before the Pass Alarm Hold period has elapsed, the alarm remains active and the Pass Alarm Hold period resets to its full value.
   3. After pass activity drops to or below the Low Water Mark and does not rise above the High Water Mark for the duration of the Pass Alarm Hold period, the alarm ends.