A note about aes signal types, A note about machine control signals, Tutorials – Grass Valley NVISION Compact CQX User Manual
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Rev 2.0 • 29 Mar 10
12. Tutorials
Routing Overview
A Note About AES Signal Types
AES matrices are different from other matrices. AES signals are numbered as stereo pairs. A 16×16
AES router has a 32×32 matrix. A 32×32 AES router has a 64×64 matrix.
If the AES router detects a video reference signal, the router operates in synchronous mode. Other-
wise, it operates in asynchronous mode.
• Asynchronous Mode
In asynchronous mode, AES ‘takes’ occur in “stereo” pairs only. AES channels 1 and 2 are a
pair, 3 and 4 are a pair, and so on. For example, you can take input pair (1,2) to output pair (5,6).
You cannot choose (even, odd) pairs. For instance, you cannot take (2,3) to any output. You
cannot take any input to an (even, odd) output.
• Synchronous Mode
When an AES router is in synchronous mode (i.e., it has a valid video reference signal), the
router’s level type is ‘Synchronous AES Mono’.
AES ‘takes’ in a “mono” partition are not paired. Each AES channel is independent. The 16×16
router has 32 independent inputs and 32 independent outputs. The 32×32 router has 64 indepen-
dent inputs and 64 independent outputs.
When an AES router is in synchronous mode, the video reference type appears in the ‘Refer-
ence’ column of the ‘Routers’ tab of the ‘View Router Crosspoints’ page (See
on page 49). If the router is in asynchronous mode, the word ‘None’ appears in that
column.
A Note About Machine Control Signals
Machine control routers operate in “machine control reverse” mode. “Machine control reverse”
means that the destination device is the controlling device (as opposed to the controlled device).
Machine control signals operate according to a serial communications protocol called RS-422 (or
EIA-422). Typically, control signals originate in an editing machine which sends commands to
playback devices. Commands include “rewind,” “skip to a certain frame,” “stop,” and so on.
For most routers, a single input can be taken to any or all of the outputs. However, a router cannot
take multiple inputs to a single output. Even if were possible, the result would be sheer noise. That
is because a router is not a mixer. It does not blend inputs
—
it takes them wholly or not at all.
Where control signals are concerned, the routers are a bit different. First, a control signal is bidirec-
tional, unlike video or audio. There is a command in one direction and a response in the reverse
direction. Each end of the connection is therefore both an input and an output. And because no
router can take multiple inputs to a single output, control signals are by definition point-to-point or
one-to-one. (Thus, when a control signal connection is made, any prior connections of its input or
output are first broken.)
Video, audio, and data signals flow continuously in a stream. Control signals occur asynchronously
and intermittently. See
Setting Up Machine Control Routers
Note
The same level type (Synchronous AES Mono) appears whether the router
is in asynchronous mode or synchronous mode.