Grass Valley NV5128 v.2.5 - Manual (Page 17)

NV5128 Multi-Format Router • User’s Guide 7
2. Introduction
Signals Types and Rates
Mixing Analog and Digital
The NV5128 frame can mix analog and digital signals within a single routing system. For example,
a digital audio input can be routed to an analog audio output. To perform this action the router uses
analog-to-digital (A/D) converters and digital-to-analog (D/A) convertors.
There are two types of A/D and D/A converter cards: one set for audio and one set for video. Ana-
log audio converter cards cannot be mixed with analog video converter cards. The input signals
type
— audio or video — must match the output signal type. For more information on converter
cards, see Active Cards on page 21.
The following is a list of audio and video inter-mix options and related delay times.
Mono Channels
AES signals are composed of several parts, including a preamble, left channel, right channel, user
bits, and channel status bits. When received as an AES signal, the signal is retained as an AES sig-
nal for internal routing to the output card. The crosspoint array on the output card breaks apart the
signal, separating out the left and right channels to create two mono channels. The mono channels
are then switched as separate signals, recombining left and right channels into new stereo signals.
The channel status bit and user bits are passed through. When the signal is distributed as an AES
output, the preamble, channel status bit and user bits are added back to the left and right channels to
create a stereo signal.
Individual left or right channels can be combined with other individual channels and distributed as
a new channel-pair combination (stereo signal). For example, a live news report may capture the
news reporter’s voice on the left channel and the background noises on the right channel. By split-
ting the AES signal into its left channel and right channel, the news reporter’s voice (left channel)
can be paired with a different background noise (right channel). If only one channel is present, the
other channel is silent.
To perform mono switching, an external AES reference signal must be connected to maintain syn-
chronization (see
Making Reference Connections on page 57). How mono signals are recombined
Machine Control (RS-422)** Yes No
* If possible, connect an external AES 48 kHz reference signal.
** Video reference is not required for operation, but ensures proper video switching.
Input and Output Options Delay
Analog audio input and analog audio output < 1.2 mS
Analog audio input and AES synchronous output ~ 658 µS
AES synchronous input and analog audio output ~ 539 µS
AES synchronous input and AES synchronous output 83.2 µs (4 samples)
AES asynchronous input and AES asynchronous output < 1 µS
Analog video input and analog video output < 20 ns
Analog video input and SD output 1 video line
SD input and Analog video output 3 µS
SD input and SD output < 20 ns
Input Signal Format Video Ref. AES Ref.