Table of Contents
Advertisement
VISTEK V1633/A & V1633/D
sdi audio multiplexer
3.4
Standard Indications
Four LEDs on the front panel show the standard and format of the input signal. The unit can operate in
either 525/60 or 625/50 formats, each of which can be component (D1) or composite (D2). Only one LED
can be on at any one time.
If there is no SDI video input then all four of these LEDs will OFF.
3.5
Module Indication
Two LEDs are used to indicate which of the two available sub-modules is fitted. Normally just one of these
LEDs will be ON. It is possible that a future module will provide one AES input and one analogue input, a so-
called hybrid module; in this case both LEDs will be ON.
3.6
Group Selections - D1
With a D1 signal, there can up to four groups of embedded audio, each group carrying two AES streams.
The V1633A can only embed on one of these groups selected using a front panel rotary switch with markings
1 to 4. The switch should be used to indicate which of the groups has been selected and not the GROUP
LEDs above. Audio can only be embedded on a group which is has no audio on it. An option is available on
S1 Switch 1, to blank all groups prior to embedding; this is an all or nothing selection. NOTE: Appending
audio onto an SDI source already containing audio data from a minority of other manufacturers multiplexers
which do not conform fully to the SMPTE spec. may cause problems if the ancillary data space is not pre-
blanked.
The 'Group' LEDs indicate which groups are occupied on the output signal, and not which group has been
selected. Thus any number of the LEDs may be ON. If there is an error on the input audio, or no signal is
present, the group light on the selected group will flash.
3.7
Reference Selection
Many installations have difficulty with embedded audio, which can often be traced to the frequency and
phase relationship between the video and AES audio. Unlike many SDI De-multiplexers the V1633A does
not require the signals to be synchronous.
multiplexed audio data streams to have no defined relationship.
To assist in operational installation the V1633A can be used to resample the audio to 48kHz with respect to
various reference signals. This may help if the audio is to be de-multiplexed at a later stage by another
manufacturer's de-multiplexer. The reference source may be either an AES signal or a video signal. The
video reference my be either the SDI input signal itself or an external analogue black and burst reference.
The front panel has a three-position selection switch used as follows:
POSn
Definition
VID/SDI
Video Ref. and SDI I/P
DCT
Direct
AES
AES Ref.
HU-V1633/A&D
In fact it is quite possible for the SDI video and the two
Description
Use one of the video references. The choice between Ref.
and SDI is made by switch 4 on the internal DIL switch. If Ref.
is selected but not present, then SDI will be used.
Pass AES without synchronisation.
Use the external AES as a reference. If this is absent then the
SDI input will be used. An AES reference of 48kHz must be
used.
9
Advertisement
Table of Contents
