Redbox User Handbook No 1
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DIGITAL AUDIO CONVERTERS
Front Panel Indicators & Controls
Fig 5-3: RB-SP1 Front Panel
Front Panel LED’s
There are four LED indicators situated on the front of the unit. The red LED on the far left of
the front panel is to indicate that power is present on the unit.
The three LED’s grouped together on the right hand side have two roles, see Fig 5-3. The
first is to indicate the synchronisation frequencies of the incoming digital signals, and the
second is to flash when a signal has been lost. These indicators are labelled individually to
show the current sync frequencies.
Type & Mode Switches
The Type and Mode switches are on the front panel – see Fig 5-3. The Type switch sets the
unit into either the Split 96 or Stereo/Mono style of operation. The Mode switch sets the unit
into Split, Bypass or Combine mode.
See Figure 5-4 for diagrammatic explanations of the different types and modes available.
Split 96 – This is a method that allows older equipment to handle 48kHz double sampled
(96kHz) digital signals. To do this, Split 96 uses two digital signals running at 48kHz, where
both sub-frames of a single 48kHz stream are used to carry information about a mono
signal, with the resultant signal of both 48kHz streams being equivalent to a stereo 96kHz
signal. The unit will also perform the same function for 88.2kHz stereo and 44.1kHz double
sampled signals.
•
In Split Mode a single stereo 96kHz signal is received into input 1 which is then
output as two separate 48kHz signals. Output 1 will contain just left channel data and
output 2 will contain just right channel data. If the signal from the input disappears
then both Outputs will be muted.
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In Combine Mode two 48kHz double sampled input signals are combined to create a
single 96kHz signal on output one. If either input 1 or 2 are lost then the output will be
muted. In this mode output 2 will always be muted.
Stereo/Mono – This allows a digital stereo signal to be separated into two mono digital
signals and vice-versa.
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In Split Mode a single stereo digital signal is routed to two digital outputs. Output
1 will contain the original left channel data on its left output and a muted signal on
