Junger Audio MIX4 Small Desktop Mixer - Manual (Page 40)

Jünger Audio-Studiotechnik GmbH
page 37
Controlling the MIX4 with SDI Interface Installed
Within the SDI (Serial Digital Interface) data stream 4 audio-groups (GR0 to GR3) can be embedded.
Each group carries 4 single channels. Normally these channels are interleaved by pairs to minimize delay
times between them. When audio channels have their origin from an AES/EBU signal one can keep this
correlation also within the SDI embedded audio domain.
The SDI interface of the MIX4 can handle 2 of these groups at a time because it corresponds with
the 4 x 2-channel concept of the interface boards. The drawing below shows the block diagram of that
interface board and a routing example that assumes GR0 and GR1 (which are the most common groups for
broadcasters) are selected for use with the MIX4 :
SDI
Receiver
SDI
Transmitter
ancillary (audio) data router
SDI
IN
SDI
OUT
10 bit parallel data
Serial link
Serial digital
2CH audio
10 bit parallel
audio data
Router
r
e
mote
Block diagram of MIX4 SDI interface
Routing example for Groups GR0 and GR1
The SDI data is converted from serial into it’s 10bit parallel format. Afterwards the ancillary data part
(see SMPTE 291M for details) of the 10bit words is taken apart while video data will pass this process
untouched. In a next step the pre selected 2 groups are taken and converted into a 4 x 2ch serial audio data
stream that will be sent to the MIX4s internal router for source selection. The other 2 groups will be
interrupted (see above example).
From the 4 output busses of the MIX4, the 4 x stereo signals are sent back to the interface.
For embedding on the SDI interface board the output signals from the busses may be combined with the
input signals to allow for transparent mode (e.g. for dolby-E pass through).
From the de-embedding side we have access to the 2 pre-selected groups. The decision is made by Setup
software (see Source section).
For the embedding side one can decide if one wants to embed the MIX4 stereo buses or pairs from the SDI
input channels. This is under direct access from the desktop remote unit.
Both interface slots can have a SDI option board installed. This allows for processing of two independent
video signals (e.g. a VTR player and a workstation recorder).
no data
no data
To source selector From bus outputs
GR 0
GR 1
GR 2
GR 3
S
D
I gr
oups
f
rom de
e
m
be
dde
r
S
D
I gr
oups
to
e
m
b
e
dd
e
r
sample configuration
by Setup software :
GR 0 and GR 1
selected
GR 0
GR 1
GR 2
GR 3