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VISTEK V1633/A & V1633/D
sdi audio multiplexer
1.
DESCRIPTION
The V1633A Audio Multiplexer is a full broadcast specification embedder of audio data into an SDI data
stream. It forms part of the Vistek V1600 range of modular interface products. It is a 3U high card, which is
fitted into either the 1U V1601 or 3U V1603 chassis from which it receives its power. It is an improved and
upgraded replacement for the V1633. The main improvements are a single board construction, and the
fitting of audio sub-boards. This means that either digital AES or analogue inputs can be accepted. Fitting
one of two available sub-modules makes the choice. There is also an audio demultiplexer module, the
V1634A, which replaces the V1634 and is fully compatible with the V1633A.
In both the V1601 and V1603 racks passive rear modules are required to interface to the outside world. For
each rack two rear modules are available depending on whether the audio is required to be analogue, digital
AES balanced or digital AES unbalanced. The rear modules are common for the V1633A and V1634A.
The SDI video may be D1 or D2 in either 625/50 or 525/60 standard. The unit automatically detects the
standard and format of the input signal and operates accordingly.
If the analogue input module has been fitted then the inputs must be balanced signals. If the digital AES
input option is fitted then the AES signals are accepted as either balanced or unbalanced, depending on the
type of rear module that is fitted to the rack.
The unit embeds audio onto an SDI video data stream according to SMPTE 272M. Any one of the available
audio groups may be embedded; the number depends on whether the signal is D1 or D2. Unlike
multiplexers from some other manufacturers the audio does not need to be synchronous with the video into
which it is to be embedded. This makes the use of embedded audio within a studio area much simpler to
implement. However it must be noted that some other manufacturers de-multiplexers will not accept
embedded audio if it is asynchronous to the SDI clock.
Another facility to assist the installation in a real environment is the ability to resample an asynchronous AES
input to an external reference, generating synchronous multiplexed audio. The external reference may be a
Black and Burst video, another AES signal, or the SDI video itself. With an ADC module, the sampling rate
is locked to whichever reference is selected.
There are three SDI outputs that are re-clocked versions of the SDI input. If the signals are D1 then all
ancillary data may be stripped off the SDI input signal prior to embedding. The EDH is regenerated on the
card. This facility is not available for D2 signals.
The unit is fully controllable over the DART remote control system.
The output of the unit has full EDH signals applied, but there is no EDH detection on the input.
HU-V1633/A&D
3
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