Digital Alert Systems DASDEC-II MANUAL - Manual (Page 51)

Digital Alert Systems: DASDEC User Manual
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When a new input source is established, refresh this page a few times to insure a consistent level quality of
OK. This page redisplays more slowly than most other DASDEC web pages, so be patient when you
access or refresh this page.
Soundcard decoder pair display table
Each table provides names and controls for two decoders to be selectively enabled and disabled and for
decoder input levels to be set. Typically, all decoders can be enabled. The DASDEC-1EN supports two EAS
decoders per stereo line input channel. This results in each soundcard device providing two decoders, one
on the left channel and one on the right channel (L1 and R1). Each decoder is displayed in a separate row in
the soundcard status table. Each row has four columns to review and configure.
The audio soundcard table columns are:
1) Decoder Name, Label and Info – The decoder base name, automatically set by server, provides an
identification tag for the decoder. The input text field provides for each decoder channel to be given a
user label for identification of the channel in other interface pages. Also, if the Audio Input Source is
set to Radio, a link to the Setup > Audio > Radio Tuners page is displayed as a convenience.
2) Audio Input Level (1..100) – Change the input level as needed until the Audio Level Status is OK
(green) or occasionally Elevated (yellow).
3) Audio Level Status – EAS Decoding is sensitive to audio input levels. Input level status is
automatically rated at Zero, Low, OK, Elevated, or High and color coded. The quality of the input level
is constantly being rated in real time per decoder on the DASDEC server. When you use the
button in the standard header of the page, the Audio Level Status quality is redisplayed. This assists
in setting the correct level setting.
Each decoder is also given a button. When a button is clicked, a WAV file of the
corresponding decoder audio input buffer is saved on the DASDEC, dated, and displayed as a web
link accessible via this web page. This can be a great aid for troubleshooting and testing audio.
The file is named based on the decoder channel name and can be downloaded via the provided web
link. In the screen shot, four snapshot files are shown:
L1 snapshot (Fri Jan 4 16:38:38 2008): L1_snapshot.wav
L1 Last Post Decoded Alert Snapshot (Tue Jan 8 09:19:26 2008):
L1_post_alert_snapshot.wav
R1 snapshot (Fri Jan 4 16:36:32 2008): R1_snapshot.wav
R1 Last Post Decoded Alert Snapshot (Wed Jan 16 11:17:12 2008):
R1_post_alert_snapshot.wav
Two of these are snapshots generated by the button, the other two, Post Decoded Alert
Snapshots, are generated automatically after decoding has finished. See the Decoded Alert Auto-
Snapshot option below.
4) Decoder Enable – Two toggles are provided to enable/disable a decoder and EAS Auto-scale. A
decoder must be enabled to decode EAS alert audio.
EAS Auto-scale is a method to automatically increase the input gain level when EAS alert data is detected.
This can result in decoding alerts that have low audio levels from the source.
Decoded Alert Auto-Snapshot checkbox
A toggle box located below the decoder status/configuration tables allows you to enable or disable the
Decoded Alert Auto-Snapshot. This feature should usually be enabled. It results in a snapshot WAV file
being generated after an alert is decoded or after a decode error is detected. This feature allows detailed
troubleshooting in the case where incoming EAS audio has resulted in decoder errors. Careful analysis of
the post-alert snapshot audio can pinpoint the nature and source of upstream EAS errors.