Rutter VDR-100G3 Installation Manual page 319

A3.5.1 Bridge Audio Self-Testing
For the bridge audio self-testing, the system will generate a tone on the speaker and detect this
tone in the captured data block. Numerous entries in the INI file are used to configure this
process. The VDR-100G3 can perform self-testing on up to three mixers and up to four mikes on
each mixer. The number of mikes to test on each mixer is set in the INI file – the
MikesOnMixer1, MikesOnMixer2, and MikesOnMixer3 fields. One mike on each mixer is tested
simultaneously.
Note! If there are three mixers incorporated in the VDR for bridge audio, the
physical connections for the VHF will be on mixer 3. The third bridge audio
mixer is physically connected as mixer 4. Therefore in the <vdrparams.ini> file
the microphones which are physically connected on mixer 4 will be set as
MikesonMixer3.
VHF channels do not support self-testing. The number of VHF channels and the corresponding
channel index are loaded from the INI file – the numVHFChannels and the VHF-ChannelX
fields, where X varies from 1 to numVHFChannels. The VHF channels do not have to be
assigned to the highest channels, but it is good practice to configure the system this way because
the hardened storage module stores only the first four captured channels (hence, it assumes that
three of these channels are bridge audio).
Each mixer has its own detection threshold, which is loaded from the INI file – the
DetectionThreshold1, DetectionThreshold2, and DetectionThreshold3 fields.
The microphone self-test is performed as follows:
1. The speaker for one mike on each mixer is turned on for the period specified in the INI
file – the ChirpLength field.
2. The RMS for the entire data record (1 second) is computed.
3. If the RMS value is greater than 0.707*detection threshold, the test is aborted. If this
happens, the background level is assumed to be too high to reliably pick out the speaker
chirp.
4. An RMS value is computed for each sub-interval; each sub-interval is the same length as
the speaker chirp duration.
5. If the RMS for any sub-interval exceeds the threshold, the chirp is declared detected and
the microphone operational.
6. When all three speakers have been sounded, the detection results are reviewed. Any
mike that has failed the test will be retried. The VDR-100G3 will wait the period specified
in the INI file (the MikeRetryInterval field) before retrying the test. The test will be retried
a maximum number of times as specified in the INI file – the MaxMikeRetrys field. If any
mike has failed all attempts, an alarm will be generated. The alarm will not clear until all
mikes have been successfully tested.
VDR-100G3/G3S Installation Manual
Appendix 3: VDRPARAMS.INI File, Rev. 1.2
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