Dolby Laboratories P/N 91659 - Manual (Page 18)

DolbyRemote Installation and Operation Dolby Digital Parameters
4-2
4.1.2 Data Rate
Data Rate determines the bit rate of the encoded Dolby Digital bitstream. All data
rate options are allowed, however, selection of the data rate is dependent on the
settings of the Audio Coding Mode, Sample Rate and Auxiliary Data parameters.
Certain low data rates may not be supported in all channel modes. For example rates
56, 64 and 80 kbps are only supported in 1/0 channel modes.
4.1.3 Clock Source
Clock Source is a parameter that specifies the reference clock source for the encoding
process as well as the reference for the output signal. The encoder will not produce a
valid output signal if a clock source is not present. A green indicator is present for a
valid source, a red indicator will be present for an invalid source. There are three
types of clock sources:
•
Digital Input: a valid AES/EBU signal must be present at the Dig In 1/2
input.
•
Ref In: a valid AES/EBU signal must be present at the Ref In input.
•
Internal (48, 44.1 or 32 kHz): always valid when selected.
Dig In 1/2 is the only input that may function as both an Input Source and Clock
Source simultaneously.
The clock source setting also controls the state of the internal sample rate conversion
(SRC). SRC is disabled for the Digital Input and Ref In - SRC Off settings. SRC is
enabled for the Ref In - SRC On and Internal clock source settings.
There are some restrictions on the clock source selection that are enforced by the
DolbyRemote application:
•
If Ref In-SRC On or an Internal clock source is selected the current Input
Format must be PCM.
•
If Digital Input or an Internal clock source is selected, the Multiplex Mode
must be disabled.
•
If Internal 32 kHz is selected the output mode must be Professional 32-bit
or the Data Rate must be less than 448 kbps.
• If an internal clock source is selected, the frequency must be consistent with
the coding delay and the auxiliary data input selection. See the DP567/DP569
user’s manual for details.
4.1.4 Audio Coding Mode
Audio Coding Mode defines the number of full-bandwidth audio channels within the
encoded bitstream and also indicates the channel format. The audio coding mode is