User`s guide

INSTALLING THE V4HD HARDWARE
31
If you choose the other device, such as a digital
mixer, as the clock master, resolve the V4HD to it
via word clock in, AES/EBU in or ADAT optical in,
as demonstrated below in Figure 3-18.
Figure 3-18: Slaving the V4HD to an AES/EBU device. For the V4HD’s
clock source, choose ‘AES/EBU’.
Or you can resolve both the mixer and the V4HD
to a third clock master device.
Figure 3-19: In this scenario, the V4HD and other AES/EBU device are
both resolved to one another via a third master word clock source.
Sample rate conversion
The V4HD is equipped with one 8-channel bank of
real-time sample rate conversion that can be
assigned to any individual input or output bank
using the “Sample Rate Convert” software option
(page 75). This feature provides a great deal of
flexibility in making digital transfers. For example,
you can:
■ Transfer digital audio into the V4HD at a sample
rate that is completely different than the V4HD
system clock rate.
■ Transfer digital audio into the V4HD without the
need for any external synchronization
arrangements.
■ Transfer digital audio out of the V4HD at double
or half the V4HD system clock rate.
■ Transfer digital audio running at a 1x or 2x
sample rate (from 44.1 kHz to 96 kHz) in or out of
the V4HD while the V4HD is running at a
corresponding 4x sample rate (176.4 or 192 kHz)
Rate conversion does not add any appreciable noise
to the audio signal (under -120 dB).
With sample rate conversion (SRC), an extra level
of master/slave clocking is added to the equation,
as demonstrated below in Figure 3-20, which
shows the clocking going on when you transfer
digital audio from the V4HD(AES/EBU out) to a
video deck (AES/EBU in) using SRC. Notice that
with SRC, the video deck is not slaved to the
V4HD’s system clock. Instead, their clocks are
running completely independently of one another.
But also notice that the video deck must still slave
to the sample-rate-converted output from the
V4HD for a clean digital audio transfer (unless it
has its own sample rate converter on its AES/EBU
input).
Master
Slave
AES/EBU OUT
AES/EBU IN
Other device
V4HD clock source
setting: AES/EBU
V4HD Sample Rate
Conversion setting: None
V4HD
(Slave)
(Slave)
AES/EBU OUT/IN
AES/EBU IN/OUT
Other device
V4HD clock source:
Word Clock In
Word clock IN
Word clock IN
V4HD Sample Rate
Conversion setting:
None
‘House’ word clock master
V4HD