Studio Technologies 5152 V.1 - Manual (Page 26)

Issue 5, September 2013 Model 5152 User Guide
Page 26 Studio Technologies, Inc.
Model 5152
Video Generator/Audio Embedder Module
and “1080” images. A configuration setting
selects whether the moving image overlay
will be active. The moving image, a box
that’s red in color, slowly moves around
and on top of whatever stored image is
present on the SDI output. The color, size,
and rate of motion of the “box” are fixed in
the FPGA’s firmware (embedded software)
and can’t be altered.
The moving image is provided specifically
so that users who are “downstream” from
the Model 5152’s SDI output are assured
that the “720” or “1080” image they are
viewing is active. And, just to clarify, if
a signal is present on the Model 5152’s
selected SDI input it will be passed on to
the coaxial (BNC) and, if present, optical
SDI outputs. The moving image will never
overlay an input signal—it can only overlay
on top of the stored image.
Audio Embedding
The Model 5152 can embed up to eight
audio channels into the SDI output signal.
These audio channels originate as four
digital audio pairs that are connected to
the digital audio inputs. Exactly how the
module embeds the audio depends on
how the module has been configured.
There are nine configuration choices. Note
that one of the choices is to not embed at
all, something that’s included primarily as
a test function. Refer to the Configuration
section for details.
There are eight signal present status
LEDs associated with the eight audio
channels that originate with the four digi-
tal audio inputs. (Two audio channels are
associated with each of the four AES3-
compatible digital audio inputs.) A signal
present LED will light when its associated
audio channel has met two conditions.
The first is that this channel (as part of a
channel pair) has been configured to be
embedded. The second is that signal level
on that channel must exceed –40 dBFS.
This level is 20 dB below the nominal
audio level of –20 dBFS for SMPTE appli-
cations. For EBU applications it will light
22 dB below the nominal –18 dBFS level.
Audio will be embedded into the SDI
output signal whether or not an SDI input
(coaxial (BNC) or optical) signal is present.
If no signal is present on the selected SDI
input the custom image will be active and
audio will be embedded into it.
If a valid signal is present on the selected
SDI input it will pass through to the coaxial
(BNC) output and, if present, the optical
SDI output. The Model 5152 will embed
audio into the SDI input signal following
the selected configuration choice. It will re-
place any audio signal already present on
the selected group or groups. To clarify, the
SDI signal connected to the input will pass
through to the output but audio already
present on the group or groups selected
to be embedded by the Model 5152 will
be replaced.
A subtle but potentially important topic
must be covered. With the Model 5152’s
embedding flexibility it’s possible that
equipment connected to the SDI output(s)
could exhibit less-than-desirable perfor-
mance. Embedded audio data will only be
present on the Model 5152’s SDI output(s)
according to the configuration setting.
There is no requirement that a specific
group, such as group 1, be active. In the
case where no valid SDI source is con-
nected to the selected SDI input, the SDI
output signal will consist of the custom
“720” or “1080” image along with the em-
bedded audio. As such, ancillary data