NVision NV1023, Инструкция по эксплуатации

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4 NV1023 SDIF-2 Distribution Amplifier
1.2 SIGNAL DISTRIBUTION APPLICATIONS
The NV1023 is a signal distribution amplifier for sending SDIF-2 digital
audio word clock to multiple destinations from a single source. It
expands the number of possible destinations for a single source from
one to as many as four.
With its input loop-through capability, several NV1023 amplifiers can
be configured to drive many more destinations. This cost-effective
topology is especially attractive when used for distributing SDIF-2 word
clock to a large number of locations. However, greater attention must
be given to good transmission-line engineering when connecting
distribution amplifiers in this manner.
It is vital that:
1. Coaxial cables have a characteristic impedance of 75 ohms.
2. The cable is terminated at the far end with 75 ohms. Connections
within the daisy chain must loop through equipment that has low
input return loss and whose input impedances are high relative to
the cable's characteristic impedance. NVISION SDIF-2 signal
distribution and processing equipment meets this criteria when
configured for high input impedance.
3. Cable lengths are minimized, and the legs of the chain past the first
connection are short and of roughly equal length.
Figure 2 illustrates a poor technique for looping a signal through
multiple pieces of equipment. The distance between devices is longer
than the distance from the source to the first device. A better topology
is illustrated in Figure 3.
The theoretical limit for the number of connections in a chain of
NV1023 distribution amplifiers is 18. The practical limit is between six
and eight, depending on cable length and quality.
Figure 4 illustrates the preferred topology for configuring multiple
NV1023 DAs for use in high fanout applications.