GRASS VALLEY 8911 AES-EBU User manual

8911
AES/EBU RECLOCKING DISTRIBUTION AMPLIFIER
Instruction Manual
071-0544-00
FIRST PRINTING: JANUARY 1999

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8911 Instruction Manual iii
Contents
Preface
About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
8911 AES/EBU Reclocking Distribution Amplifier
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Input Section. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Output Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Linear Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Module Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Loopthrough Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Testpoints and Indicators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Index

iv 8911 Instruction Manual
Contents

8911 Instruction Manual v
Preface
About This Manual
This manual describes the features of a specific module of the 8900 Series
Distribution Amplifier family. As part of this module family, it is subject to
Safety and Regulatory Compliance described in the 8900 Series frame and
power supply documentation (see the
8900 Series User’s Guide ).

vi 8911 Instruction Manual
Preface

8911 Instruction Manual 1
8911 AES/EBU Reclocking
Distribution Amplifier
Introduction
The 8911 module is a digital audio 1x8 distribution amplifier that provides
reclocking of the digital signal. The amount of digital audio is ever
increasing as studios and broadcast facilities transition to digital transmis-
sion. The 8911 offers a low cost method of reclocking AES/EBU digital
audio signals. Reclocking reduces the signal jitter resulting from numerous
passes through other equipment such as audio routers and switchers. The
8911 fits into the 8900 series frames which offer passive loop-through
inputs, high density and a wide range of distribution and format conver-
sion functions.
The 8900 Series product line is a family of serial digital distribution ampli-
fiers (DAs) and signal processors that reside in a 2 rack unit frame which
accommodates up to ten modules. A variety of modules are available that
can provide fanout, timing/reclocking, monitoring, or error detection and
handling capabilities. Modules are selected by the user to suit their partic-
ular requirements.
The 8911 distribution amplifier provides:
■ Signal reclocking to reduce jitter,
■ Support of 32, 44.1 and 48 KHz sample rates,
■ Eight outputs for ample distribution,
■ Loop-through input enabling redundant system design,
■ Accepts input cable lengths of up to 1000m (Belden 8281 or equivalent),
and
■ Ten module capacity in a 2 rack unit 8900 frame.

2 8911 Instruction Manual
8911 AES/EBU Reclocking Distribution Amplifier
Functional Description
The 8911 has one loop-through, high impedance input and produces eight
75-Ohm outputs. The AES/EBU data is reclocked by means of a phase-
locked-loop. Refer to Figure 1 while reading the following description.
Figure 1. 8911 AES/EBU Reclocking DA Block Diagram
Input Section
The input channel is loop-through and is not terminated (the differential
input is high impedance). The input signal comes from the 50-pin con-
nector, P1, and feeds a transformer, T1. Transformer coupling on the input
eliminates common mode noise. The output side of the transformer feeds
the differential line receiver of AES/EBU receiver U3.
The AES/EBU receiver reclocks the data for its AES/EBU data stream. The
mode pins 17, 18, 23 and 24 are set to pass the entire AES3 signal with the
preamble. The receiver has an incoming audio sample frequency range of
25 KHz to 55 KHz.
Output Section
After it is reclocked, the serial data is routed to a quad EIA-485 line driver,
U4. The line driver chip drives eight output lines.
Phase
Locked
Loop
Input Section
AES/EBU Receiver
U3
Output Section U4
Differential
Line Rx
Output
Line Driver
Output
Line Driver
AES
Outputs
T1
0544_00
Reclocker
Loop-through
AES Input
Lock LED

8911 Instruction Manual 3
Specifications
The outputs feed a resistive network that performs three functions:
■
Attenuates the signal to become 1 volt peak-to-peak,
■
Creates a 75 Ω output resistance matching the cable impedance, and
■
Limits the rise and fall times to meet the AES/EBU specification.
Linear Regulator
The voltage regulator is a monolithic integrated circuit with a fixed voltage
output of +5 volts. This regulator employs internal current limiting and
thermal shutdown.
Specifications
Table 1. 8911 Specifications
Parameter Value
Input
Number 1 loopthrough
Signal type AES/EBU digital audio, per AES3id:1995 and SMPTE 276M
Connector 75
Ω BNC
Return loss >25 dB, 0.1 to 6 MHz
Outputs
Number 8 reclocked
Signal type AES/EBU digital audio, per AES3id:1995 and SMPTE 276M
Connector 75
Ω BNC
Return loss >25 dB, 0.1 to 6 MHz
Performance
Sample Rates 48KHz, 44.1KHz, and 32KHz (Automatic selection)
Environmental
Operating temperature range 0 to 45° C, noncondensing
Non-operating temperature range -10 to +70° C, noncondensing
Power Requirements
Supply Voltage +12 Volts
Power dissipation 3 Watts
Physical
Frame Resides in standard 2 rack unit 8900 Series frame

4 8911 Instruction Manual
8911 AES/EBU Reclocking Distribution Amplifier
Module Installation
There are ten cell locations in the frame to accommodate either analog or
digital modules. These are the left ten slots. Refer to Figure 2.
The two cells on the right are allocated for the power supplies. For addi-
tional information concerning the Power Supply module, refer to the
Power Supply manual.
The third cell from the right is allocated for the Controller module. This
module provides the interface for the forced air cover, as well as the SMPTE
269M fault reporting (health alarm). For additional information concerning
the Controller module, refer to the Controller manual.
Figure 2. 8900 Series Frame
To install a module into the frame, follow these steps:
1. Insert the module into the frame, connector end first, with component
side of the module facing to the right and ejector tab to the top.
2. Verify that the module connector seats properly against the backplane.
3. Press the ejector tab in to seat the module in place.
Controller
Module
(only)
Any 8900 Module Power
Supplies
(only)
0515_04