User`s guide

User’s Guide ADI-8 DS © RME

8.5 Clock Section

The source and frequency of the unit's clock is configured in the CLOCK section. The button

CLOCK lets you step through the options external clock (Word, AES, ADAT) and internal clock,

and sets the sample rate range for both an external and the internal clock.

WCK, AES, ADAT

Defines the corresponding input as clock reference. A missing or invalid clock source signal is

indicated by flashing of the corresponding LED.

INT (Master Mode)

Activates the internal clock.

With a setting of INT (internal clock) it is mandatory that the clock rate of the sources is

synchronous to the ADI-8 DS. Therefore the external device has to be synchronized to the

ADI-8 DS word clock output or AES/ADAT output.

The ADI-8 DS thus has to be master, all devices connected to it must be slave. In order to avoid

clicks and drop outs due to faulty or missing synchronicity, a special process called SyncCheck

compares the incoming data and the ADI-8 DS internal clock. The SYNC state is indicated by a

flashing (error) or constantly lit (OK) LED.

44.1, 48

Activates the internal clock at 44.1 kHz or 48 kHz.

DS, QS

With the DS LED additionally lit, the sample rate will be 88.2 or 96 kHz, with QS lit it will be

176.4 or 192 kHz.

A selection of DS and QS is also possible when

using external clock (Slave). If the ADI-8 DS should

operate at 192 kHz, but receives a synchronous

word clock of 48 kHz, the button STATE allows to

activate DS or QS mode. This way, AD-conversion

and digital outputs are configured to operate in the

frequency ranges Single Speed, Double Speed or

Quad Speed.

Using AES as clock source the STATE key is disabled, as the sample rate is clearly given by

the input signal. ADAT misses such information, therefore when ADAT is clock source the

STATE has to be set manually.

Single Speed

All outputs carry a signal in the range of 32 kHz up to 48 kHz.

DS (Double Speed)

The AES outputs 1-8 carry a signal in the range of 64 kHz up to 96 kHz. ADAT stays at no

higher than 48 kHz, with the data transmitted in the S/MUX format.

QS (Quad Speed)

The AES outputs 1-8 carry a signal in the range of 176.4 kHz up to 192 kHz. ADAT stays at no

higher than 48 kHz, with the data transmitted in the S/MUX4 format. Therefore ADAT is limited

to 4 channels (2 per optical output) in this mode.