18
User's Guide ADI-6432R BNC © RME
11. Word Clock
11.1 Word Clock Input and Output
SteadyClock
guarantees an excellent performance in all clock modes. Its highly efficient jitter
suppression refreshes and cleans up any clock signal, and provides it as reference clock at the
BNC output (see section 14.5).
Input
The ADI-6432's word clock input is active when WCK is chosen in the clock section. The signal
at the BNC input can be Single, Double or Quad Speed, the ADI-6432 automatically adapts to it.
As soon as a valid signal is detected, the WCK LED is constantly lit, otherwise it is flashing.
Thanks to RME's
Signal Adaptation Circuit
, the word clock input still works correctly even with
heavily mis-shaped, dc-prone, too small or overshoot-prone signals. Thanks to automatic signal
centering, 300 mV (0.3V) input level are sufficient in principle. An additional hysteresis reduces
sensitivity to 1.0 V, so that over- and undershoots and high frequency disturbances don't cause
a wrong trigger.
The ADI-6432's word clock input is shipped as high impedance
type (not terminated). A push switch allows to activate internal
termination (75 Ohms). The switch is found on the back beside
the BNC jacks. Use a small pencil or similar and carefully push
the blue switch so that it snaps into its lock position. Another
push will release it again and de-activate the termination.
Output
The word clock output is constantly active, providing the current sample frequency as word
clock signal. In master mode, the word clock will be fixed to 44.1 kHz or 48 kHz (DS x 2, QS x
4). In any other case the sample rate is identical to the one present at the currently chosen
clock input. When the current word clock source fails, the last valid sample rate will be held
automatically.
The word clock signal received by the ADI-6432 can be distributed to other devices by using the
word clock output. With this the usual T-adapter can be avoided, and the ADI-6432I operates as
Signal Refresher
. This kind of operation is highly recommended, because
•
Input and output are phase-locked and in phase (0°) to each other
•
SteadyClock removes nearly all jitter from the input signal
•
the exceptional input (1 Vpp sensitivity instead of the usual 2.5 Vpp, dc cut, Signal Adapta-
tion Circuit) plus SteadyClock guarantee a secure function also with most critical word
clock signals.
Thanks to a low impedance, but short circuit proof output, the ADI-6432 delivers 4 Vpp to 75
Ohms. For wrong termination with 2 x 75 Ohms (37.5 Ohms), there are still 3.3 Vpp at the out-
put.
Summary of Contents for ADI-6432(r)
Page 5: ...User s Guide ADI 6432R BNC RME 5 User s Guide ADI 6432R BNC General...
Page 13: ...User s Guide ADI 6432R BNC RME 13 User s Guide ADI 6432R BNC Usage and Operation...
Page 25: ...User s Guide ADI 6432R BNC RME 25...
Page 28: ...28 User s Guide ADI 6432R BNC RME...
Page 29: ...User s Guide ADI 6432R BNC RME 29 User s Guide ADI 6432R BNC Technical Reference...
Page 37: ...User s Guide ADI 6432R BNC RME 37 16 Block Diagram...
