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Wiki > Main > VolumeTriggeredRecording (compare)

Difference: VolumeTriggeredRecording (r3 vs. r2)

Volume Triggered Recording

This describes how the mechanism of triggered recordings works. This feature is not yet included in the cvs but available via the patch tracker.

Parameter definitions

The trigger is defined by servaral several parameters:

Start threshold:

The threshold that must be exceeded to start a recording.

Start duration:

The minimal duration that the trigger must exceed the start threshold to meet the start conidition.

Start dropout:

The maximal time that the signal may drop below the start threshold within the start duration without resetting the trigger. This is a parameter that usually isn't adjustable by the user. It defaults to Min(start duration / 2, 2 seconds)

Stop threshold:

The signal must drop below the stop threshold to stop a recording

Stop hold:

The timespan the signal must fall below the stop threshold to really stop the recording.

Stop gap:

The minimal duration the signal must have fallen below stop threshold before a retrigger is allowed. The gap time is smaller than the stop hold time. A retrigger can cause a file split.

trigger mode:

off trigger is not used
once The trigger starts, stops but does not restart
repeat The trigger starts, stops, splits/restarts

Trigger start:

When the level rises above the start threshold the start duration begins. A dropout happens when the signal falls below the start threshold for a short while. When the signal drops below the start threshold for longer than the max dropout time it is not regarded as a dropout and the trigger is reset.

                |<-- start duration -->|
                |                      |
                |     |max dropout|    |
                |     |           |    |
                |     |dropout|   |    |
                |     |       |   |    |
                | ___ |       | __|____|_
                |/   \|       |/         \
strt thrsh------/-----\-------/-----------\--------
               /       \_____/             \
              /                             \      
             /                               \
signal  ____/                                 \____

Trigger normal stop:

When the signal falls below the the stop threshold for longer than stop hold time the recording is stopped.

               |<- stop hold -----------------> |
               |                                |
               |<- gap ->|                      |
               |         |                      |
signal______   |         |                      |
            \  |         |                      |
strt thrsh---\-|---------|----------------------|---
              \|         |                      |
stp thrsh------\---------|----------------------|--
                \________|______________________|__

Trigger retriggers:

When the signal has fallen below the stop threshold for longer than the gap time retriggering is enabled. When the level rises above the start threshold a retrigger may occur. Wether a retrigger is fired depends on the same rules as for the initial trigger. That means that the signal must remain above the start threshold for the start trigger duration with dropouts that don't last longer than the maximal dropout time.

               |<------------ stop hold -----------------> |
               |                                           | 
               |               | start duration|           |
               |<- gap ->|     |               |           |
               |         |     |mx drpout|     |           |
signal______   |         |     |       __|_____|___________|___
            \  |         |     |__    /                    |  
strt thrsh---\-|---------|-----/--\--/---------------------|---
              \|         |    /    \/                      |
stp thrsh------\---------|---/-----------------------------|---
                \________|__/                              | 

Trigger continue:

The recording continues if - the signal rises above the stop threshold during gap time - the a trigger during the stop hold time fails - after the gap time the level rises above the stop threshold but does not exceed the start threshold within the dropout time.

               |<---------- stop hold -------------------> |
               |                                           |
               |<- gap ->|   | start duration|             |
               |         |   |               |             |
signal______   |         |   |mx drpout|     |           __|___
            \  |         |   |         |     |          /  |  
strt thrsh---\-|---------|---|---------|-----|---------/---|---
              \|         |   |__    ___|_____|________/    |
stp thrsh------\---------|---/--\--/-----------------------|---
                \________|__/    \/                        | 

see also the TriggerManual

r3 - 06 Apr 2005 - 13:33:07 - LinusNielsenFeltzing

Revision r3 - 06 Apr 2005 - 13:33 - LinusNielsenFeltzing
Revision r2 - 17 Oct 2004 - 14:17 - PhilippPertermann
Copyright by the contributing authors.