Eventide H8000FW, Operating Manual, Page: 97 / 206

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Sample Rate Conversion (SRC)
In general you need to make sure that any digital inputs are synchronized to the system
sampling rate.
If for whatever reason you cannot synchronize
the AES/EBU 1-4 (1-8 on H8000FW) or S/P
DIF 1/2 digital inputs to the system sampling
rate, use sample rate conversion (SRC). The sample rate conversion pages are the
"bottom" menu pages under
clock
in the
SETUP
area. By turning
SRC Mode on
for the
appropriate digital input, the H8000FW will adjust the input sampling rate to match the
system sampling rate. The sample rate before conversion is displayed in the
Input SR
x/x
field. In this example, our internal clock rate is 48kHz. The SRCs are converting these
44.1kHz inputs to 48kHz.
The sample rate conversion algorithm is of a high quality and its presence is normally
undetectable without the use of expensive test equipment. Nevertheless, the true
audiophile will try to synchronize the input devices to the H8000FW without using
sample rate conversion in order to achieve the best possible results.
Note that sample rate conversion is only available on the above inputs – other digital
inputs need to be locked if they are used.
Word Clock Termination
Any cable has a characteristic impedance that should be matched to both the signal source and
destination impedance for best results with high speed sharp edged signals such as Word
Clock. This becomes more important with longer cables.
Most Word Clock signals are generated with 50 Ohm source impedance, whereas the
BNC cables used to connect to them may have 50 or 75 Ohm impedances – clearly the
former are to be preferred.
So, we have covered the source and the cable – what about the destination ? If we only
have a single destination it is easy – the destination must also be 50 Ohm – this is ensured
by the use of
termination . An input will be either terminated meaning its impedance is set
to 50 Ohm, or un-terminated meaning it has a high impedance that will not load the cable.
With multiple destinations only the one at the end of the cable
needs to be terminated – intermediate destinations need not and
should not be terminated, as long as the “stub length” of the cable
to them is short. These should be connected by the use of a BNC
“T” connector or splitter attached directly to their inputs so as to