Follow Clock (Fc); Word Clock Out (Co) - RME Audio ADI-8 QS User Manual

Units Delay
2 3
3 6
4 9
5 12
6 15
7 18
8 21
As shown in the table, activating DC causes a constant delay of 21 samples in Single Speed,
no matter how many devices are connected serially. In Double Speed the delay is 18, in Quad
Speed 12 samples. The in most cases slightly increased delay is outweighed by the big advan-
tage of sample-aligned I/Os when using multiple units.
Delay Compensation always uses the worst case, the operation of 8 units, but delays the sig-
nals individually. The amount of the respective delay is solely derived from the current ID, no
matter if it has been assigned manually or by Auto ID.

9.9 Follow Clock (FC)

Default: Off
Available settings: On, Off
The signal at the word clock or AES input can be Single, Double or Quad Speed, the ADI-8 QS
can use it in any case, independent of its current clock range. When activating the option Follow
Clock the ADI-8 QS follows the input clock 1:1. At 96 kHz the DS LED will light up automatically,
at 192 kHz the QS LED. This function is automatically deactivated for the I64 MADI Card and
the ADAT input, as it is not possible to detect the sample rate range automatically.

9.10 Word Clock Out (Co)

Default: FS
Available settings: Si, FS
Si stands for Always Single Speed, FS for the current sample rate or Follow Sample rate. In
default state (FS) the word clock output follows the current sample rate up to 192 kHz. Selecting
Si causes the word clock output to always stay within the range of 32 kHz to 48 kHz. So at 96
kHz and 192 kHz sample rate, the output word clock is 48 kHz.
Note: A reliable sample-accurate synchronicity between multiple devices having digital inter-
faces in S/MUX technology (ADAT and MADI*) at sample rates in the Double Speed and Quad
Speed range is only possible when all units are synced by Single Speed word clock. Because of
the S/MUX method the device else can not know which of the incoming 2 (DS) or 4 (QS) word
clock edges is the right one.
* With the ADI-8 QS this limitation is also valid for the AES output, as the device internally handles all the data streams
in S/MUX mode.
20
Delay DS Delay QS
6 12
12 -
18 -
- -
- -
- -
- -
User's Guide ADI-8 QS © RME
DC DC DS DC QS
21 18 12
21 18 -
21 18 -
21 - -
21 - -
21 - -
21 - -
21 samples @ 48 kHz
equal 437 µs.
18 samples @ 96 kHz
equal 187 µs.
12 samples @ 192
kHz equal 62.5 µs.