Eventide H8000FW, Руководство по эксплуатации, Страница: 98 / 206

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ensure the shortest possible stub length . Using multiple terminations is wrong, both because
twice 50 Ohm in parallel gives 25 Ohms (wrong !) and also because it increases loading on
the source.
H8000 and H8000A are shipped with termination in place meaning that they can be used
at one end of a Word Clock cable without changes. To use them in the middle of a chain
the termination should be disconnected by removing the black jumper on the
motherboard directly behind the Word Clock connector.
H8000FW has no internal termination and can be used in the
middle of a Word Clock cable without change. To use it at the
end of a chain, external 50 Ohm termination must be applied. To
do this, you will need a BNC T piece as shown above and a 50
Ohm terminator as shown on the right. These may be supplied
with the H8000FW or obtained from one of many suppliers.
Connect the T piece to the Word Clock input, the cable end to
one side and the terminator to the other.
W
ORD
L
ENGTH
(B
ITS
)
Input Word Length
As mentioned in the introduction to this section, the H8000 assumes that the signals at
the digital inputs are all 24-bit. Things work out regardless of the actual word length of
the input signals because, for example, the 16 bits in a 16 bit signal correspond to the 16
"most significant" bits in a 24 bit signal. The 8 "least significant" bits are left "blank," to
be filled in by subsequent processing.
If, however, the device sending the H8000 digital
signals supports the protocol, you can see the word
length at the inputs to the H8000. Go to the
format
menu page in the
SETUP
area. The fields
on the left display the input word length (16 bits, 24
bits, and two unlocked signals in this case). The
H8000 user can display and change these settings
on Digital channels 1-8, while H8000A and H8000FW can only show channels 1-4.
If the input bits are unknown as in the case of an S/P DIF input, the field reads, quite
logically, "
unknown
." If a digital input is unlocked (not valid or not connected), the field
will read "
**
."