RME Audio ADI-192 DD, User Manual

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User's Guide ADI-192 DD © RME
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8. The Sample Rate Converter
8.1 General
The ADI-192 DD includes an eight-channel sample rate converter (SRC). Its technical specifica-
tions indicate an exceptional conversion quality, formerly known only from synchronous SRC
devices. The ADI-192 DD's SRC is asynchronous, yet provides a phase-locked conversion
across all eight channels. If the incoming signals are phase-aligned, the SRC converted output
signals are as well. Deviations in the sub-sample range are a thing of the past.
A SRC allows a conversion of the sample rate in real-time. The 24 bit converters used in the
ADI-192 DD operate practically without loss of signal quality, so no audible artefacts or noise is
added. In fact, the SRC works so well that we could recommend to just leave it on at all times,
thus eliminating all clock problems right from the start.
The ADI-192 DD offers a maximum conversion rate of 1:7 or 7:1, respectively. Thus, 192 kHz
can be converted to any sample rate down to 32 kHz, and 32 kHz can be converted to any fre-
quency up to 192 kHz.
When using the internal clock, every SRC also works as a jitter killer. However, the ADI-192 DD
is equipped with SteadyClock, thus operating as perfect jitter killer with any clock source.
An SRC not only converts sample rates, it also serves as a clock decoupler. With SRC active,
even non-synchronizable devices (CD-players, DAT machines, etc.) can be used in a setup of
digital devices, just as if they were externally synchronized. The SRC decouples input and out-
put clock, sets the output clock to the common reference, thus allowing the combination of dif-
ferent clock-sources without any clicks or dropouts.
8.2 Operation
The button SRC INPUT SOURCE defines the data path in which the sample rate converter will
be inserted: AES, TDIF or ADAT. With no LED lit, the SRC is deactivated. Selecting the same
input in the OUTPUT section as in the SRC INPUT SOURCE section, the LED SRC indicates
an activated sample rate conversion. Selecting the function SRC in the OUTPUT sections is not
necessary.