Digital Clock Configuration - Lab.gruppen PLM Series Operation Manual

12 APPLICATION GUIDE
rehearsal situations to discover what maximum length
can be used, and then to not use more than 75% of
this length "on the road". It is also good practice to
ensure that interconnect cables (particularly mixer-
stage) of various lengths are available, and to use the
shortest that each venue will permit.
It is also recommended that the same types of cable
and connectors are used throughout the system,
as this will minimize any likelihood of impedance
mismatch. If passive splitters are used, they should
be situated as close as possible to the PLMs (or other
devices) connected to their outputs, using cables as
short as possible.

12.6 Digital Clock Configuration

In order to provide a highly flexible and robust audio
processing system, PLM Series devices are equipped
with a configurable clocking system. To fully take
advantage of the flexibility the system needs to be
configured with respect to clock source and base
rate.
The clocking system can either rely on its internal
clock, or it can sync to an external incoming clock
source via the PLMs AES digital input. There are
two options for clock source configuration: manual
configuration or automatic detection.
▸ Manual configuration mode: The user can select
either the internal or the external clock. The clock
remains fixed at the configured source.
▸ Automatic detection mode: The PLM automatically
chooses the available clock with the highest
priority according to the following priorities:
1. The incoming external clock via the AES
digital input
2. The internal clock.
The PLM always monitors the AES digital input and
will seamlessly switch the clock source back and forth
depending on the availability of an AES signal.
There are two options for the incoming clock base
rate configuration: 44.1 and 48 kHz The PLM must
be configured to one of the base rates and it will then
only lock to incoming AES signals that are based on
68 PLM Series Operation Manual
that rate. If failing to lock to the incoming clock the
clock status will be reported as slipping and the audio
signal will be distorted.
▸ 44.1 kHz: Includes sample rates equal to the base
as well as the multiples 88.2 and 176.4 kHz.
▸ 48 kHz: Includes sample rates equal to the base
as well as the multiples 96 and 192 kHz.
The available options for configuring the PLM Series
digital clock are as follows:
3. Auto 44 detection
4. Auto 48 detection
5. Manual 44 config
a. External AES clock
b. Internal clock
6. Manual 48 config
a. External AES clock
b. Internal clock
The default configuration is Auto 48 detection,
which is appropriate for most professional audio
applications.
For further information on the user interface
please refer to the Dolby Lake Controller
Manual and the Sample Rate Converter
Clock (SRC Clock) configuration in section
7.2.1.
When enabling Dante, the PLM will sync
its digital clock to the Dante master. If using
the AES input in conjunction with having
Dante enabled, the Dante master must have
AES signals derived from the same word
clock.