Studio Technologies 5152 V.3 - Manual (Page 8)

Issue 2, June 2013 Model 5152 User Guide
Page 8 Studio Technologies, Inc.
Model 5152
Video Generator/Audio Embedder Module
connection time helps to ensure that an
accidental format and rate change won’t
occur.) However, there may be situations
where maintaining the format and rate of
the internally-generated signal is important.
To support this condition one configuration
choice allows the automatic format/rate
selection function to be disabled.
Audio Embedding
The Model 5152 allows four stereo digital
audio signals to be embedded into the SDI
output signal. The eight channels of au-
dio will always be embedded, whether or
not a source is connected to the module’s
SDI input. Eight configuration choices al-
low flexibility as to where the digital audio
inputs will be embedded into the SDI output
signal. A range of applications can be sup-
ported by taking advantage of the module’s
ability to embed into groups 1, 2, 3, or 4.
The four digital audio inputs are 75 ohms,
unbalanced, and follow the AES3 standard.
They are intended for use with broadcast-
standard “24-bit, 48 kHz” digital audio
signals. Advanced sample-rate-converter
circuitry ensures excellent performance
with signals that are asynchronous with
each other and the Model 5152’s internal
timing.
The Model 5152’s digital audio inputs are
directly compatible with the digital audio
output provided by the Studio Technologies’
Model 5110 Mic/Line Input Module. Up to
four Model 5110 modules can be directly
connected, supporting eight mic/line inputs.
A major Model 5152 feature is its ability
to embed audio into the SDI output sig-
nal whether or not an SDI input signal is
present. If a valid SDI signal is present on
the input then the Model 5152 will embed
audio data into that data stream. If an SDI
signal is not present on the SDI input,
embedding will continue but now will be
associated with the custom image. In this
way embedded-audio transport will always
be supported.
When audio is being embedded into an
externally-connected SDI signal it will re-
place any incoming embedded audio that’s
already present. However, any embedded
audio present on groups that are not being
embedded by the Model 5152 will correctly
“pass through” to the SDI output. This is
important when SDI input signals that
already include embedded audio, such as
from portable ENG-type cameras, are con-
nected. Such devices typically embed two
or four microphone audio channels into
group 1, which need to pass through the
Model 5152 without interference.
It’s important to note that when changing
from an external SDI signal to the internal
generator (or vice-versa) the SDI output,
including embedded audio, will momentari-
ly lose timing and some video and audio
“glitches” may be present. For the intended
Model 5152 applications this should
not prove to be an issue but is worth
mentioning.