Word Clock Connections And Settings; About Word Clock; Selecting The Word Clock Master - Yamaha PM5D Owner's Manual

Word clock connections and settings

This section explains the word clock settings required in order to send or receive digital audio between the PM5D and an
external digital device.

About word clock

When digital audio signals are being sent or received
between multiple devices, the devices must process the
audio signals at the matching timing. For example if the
audio signal processing is not synchronized, the signals will
not be transmitted correctly and unpleasant noise will
occur even if both devices are set to the same sampling
frequency.
The signal used to synchronize digital audio signal process-
ing is called "word clock." Normally, one device transmits
a reference word clock signal, and the other devices receive
this word clock signal and synchronize to it. (The transmit-
ting device is called the "word clock master" and the
receiving devices are called "word clock slaves.")
The word clock can be synchronized between the PM5D
and external devices in either of two ways; you can send/
receive a word clock signal by itself, or use the clock data
that is included in a digital audio signal.
The WORD CLOCK IN/OUT connectors on the rear
panel of the PM5D are used to send/receive a word clock
signal by itself. In general, word clock connections can be
made in either of the following two ways.
Using daisy-chain connections
In this method, the signal is distributed sequentially; the
WORD CLOCK OUT connector of the first device is con-
nected to the WORD CLOCK IN connector of the second
device, and so on. Turn ON all of the 75Ω ON/OFF
switches. This method is not recommended for large
systems.
Word clock
master
75Ω ON/OFF= ON
WC OUT (BNC)
WC IN WC OUT WC IN
(BNC) (BNC) (BNC)
Device A Device B
Word clock Word clock
slave slave
75Ω ON/OFF= ON 75Ω ON/OFF= ON
Using a word clock distribution box
In this method, a special word clock distribution box is
used to distribute the signal from the word clock master to
multiple word clock slaves. Turn ON all of the 75Ω ON/
OFF switches.
Word clock
Word clock
WC OUT
master
distribution box
(BNC)
75Ω ON/OFF= ON
WC IN (BNC) WC IN (BNC)
Device A Device B
Word clock Word clock
slave slave
75Ω ON/OFF= ON 75Ω ON/OFF= ON
WC OUT WC IN
(BNC) (BNC)
Device C
Word clock
slave
75Ω ON/OFF= ON
WC IN (BNC) WC IN (BNC)
Device C Device D
Word clock Word clock
slave slave
75Ω ON/OFF= ON 75Ω ON/OFF= ON
PM5D/PM5D-RH Owner's Manual
If an external device does not have WORD CLOCK IN/
OUT connectors, the clock data included in the digital
audio signal is used. In this case, both the digital audio sig-
nal and the clock data are sent from the DIGITAL OUT
jack of the word clock master to the DIGITAL IN jack of
the word clock slave.
Digital audio signal
+
Clock data
DIGITAL
OUT
Device A
Word clock
master

Selecting the word clock master

When digitally connecting the PM5D to an external device,
you must select the source that will be the word clock mas-
ter for the system.
1 Repeatedly press the [SYS/W.CLOCK] key of
the DISPLAY ACCESS section until the WORD
CLOCK screen appears.
WORD CLOCK MASTER CLOCK SELECT area
In this screen you can select the master clock, and
check the input signal synchronization status for each
slot or jack.
Note
When you switch the word clock source, noise may occur due
to loss of synchronization. You must lower the level of your
monitoring equipment before you perform the following
operation.
Operating section
4
DIGITAL
IN
Device B
Word clock
slave
31