NV5128 Multi-Format Router • User’s Guide
25
2. Introduction
Active Cards
before being forwarded to the motherboard. This means that a wide variety of AES-compatible dig-
ital audio inputs with sample rates from 22
kHz to 108
kHz can be integrated into a synchronous
AES environment or converted to analog audio outputs as desired.
The receivers buffer the input, extracting audio data, sample clock, and applicable channel status
information. The clock and data signals are then processed by an asynchronous SRC and the rate-
converted data reformatted and combined with the appropriate channel status information and user
bits. Reference clock signals from the control card are used to synchronize the data to create an
AES format signal. The signal is then forwarded to the motherboard for distribution to output cards.
shows the signal path through the SRC.
Figure 2-19. Signal Flow through SRC Card
Analog Audio
Incoming and outgoing analog audio signals are received or distributed through four DB25 connec-
tors, housed on a backplane. (See
The analog audio input card and output card feature DIP switches and a jumper that allow gain and
mute detection to be set. (See
on page 69.) In addition, using a separate
DIP switch set, the operating level of the card can be set to match the operating level of the facility.
By matching the incoming signal level, there is less degradation of the signal when it is converted
to digital for internal routing in the router. For information on setting analog input card levels, see
Input Card
The analog audio input card (
EM0585
) receives up to 16 stereo signals (32 mono channels) through
passive backplane I/O connectors. Inputs are forwarded to an analog-to-digital (A/D) converter.
The A/D converter accepts two analog signals, either left and right channels of a stereo pair or two
mono channels. The A/D converter is rate locked to the systems clock on the control card, convert-
ing the signals to a sample rate of 48
kHz and into AES compatible bit streams containing the sam-
pled data. The audio data is set to a common sample point, which is important for proper phase
alignment of audio signals. The resulting synchronous AES signals are sent to the motherboard.
Output
The analog audio output card (EM0586) receives 128 stereo inputs from the motherboard. The sig-
nals are then sent to a crosspoint array of 128 inputs x 16 outputs (256 inputs x 32 outputs mono)
for switching and then on to a digital-to-analog (D/A) converter which converts the signal from
digital format to analog. From the D/A converters, the analog signals have low-pass filtering and
I/O
Connectors (up to 16)
AES
Recr
Input Card
Transformer
Coupled
Motherboard
I/O
Connectors (up to 16)
Control Card
SRC
Timing
Control and
AES3
Encoder
Reference Clock Signal
Channel Status Bits
Summary of Contents for NV5128
Page 1: ...User s Guide NV5128 Multi Format Router...
Page 44: ...34 Rev 2 3 14 Oct 08 2 Introduction Active Cards...
Page 92: ...82 Rev 2 3 14 Oct 08 6 Maintenance Obtaining Service...
Page 102: ...92 Rev 2 3 14 Oct 08 8 Glossary Glossary...
Page 106: ...96 Rev 2 3 14 Oct 08 A Part Numbers Power Supplies...
Page 114: ...104 Rev 2 3 14 Oct 08 Index...
