Cisco D9887B, Руководство по установке и настройке

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Appendix E
D9887B Receiver Audio Explanation
244 78-4043743-01 Rev A
Audio Output Settings
The digital audio services may be set to "PCM" (AES) or "Raw" as an output. This
applies to all available sources. The "PCM" setting will pass an AES stream, or
automatically down mix an AC-3 Dolby stream to two channels. "Raw" simply
passes thru the Dolby AC-3 data stream to be decoded by an external decoder such
as the Dolby 569. The analog channels can be assigned to any of the digital services.
The analog gain may be adjusted for the desired level. The gain setting does not
affect the level of either the embedded audio or the digital services. A setting of 7
provides an output of approximately 0 dBu for a digital signal level of -20 dBFS. To
check the audio output level, set "User / Custom1 / L/R" to disabled. This will
remove any signal processing in the down mix. Set the digital service to be measured
to "PCM." A test stream of -20 dBFS will output from the digital services as -20 dBFS.
If the analog channels are set to a gain setting of 7, the output should be -0.7 dBu
plus or minus 0.5 dBu. Each gain number increments or decrements approximately
2.5 dBu per step. When you are setting the output levels, it is suggested that an AC-3
stereo tone (2.0) be used as the source. Do not use a Dolby AC-3 5.1 tone source as
your test signal. The five channels of equal tones will down mix such that one
channel will be more than twenty dB greater than the other.