Grass Valley 8921ADT - Manual (Page 48)

48 8921ADT Instruction Manual
Functional Description
Functional Description
Refer to the block diagram in Figure 21 for the following functional
description.
The 8921ADT receives four channels of balanced analog audio differen-
tially to reduce common mode interference. The audio inputs are con-
verted into single-ended signals that feed a gain amplifier where the
maximum input levels can be adjusted to just below the clip point for the
analog to digital converter.
Figure 21. 8921ADT Functional Block Diagram
Audio
In 1
Audio
In 2
Audio
In 3
Audio
In 4
Reference
In
Fault
Pwr Comm
Conf
Ovr
Frame
Bus
Balanced Analog
Audio Inputs
+
–
+
–
+
–
+
–
Maximum Input
Level Adjust Delay Adjust
> -40 dBFS/Clip 1-4
Trk On
AES 1 Mode
AES 2 Mode
Control
Control Paddle
Locked
Bank 2 LED
Silence Tone
Input
Timing
to Module
Control
to Module
1 kHz/400 Hz
Tone Gen
Input
Output
Processing
AES 1/ 2
Gain
Status Bits
Delay Adjust
Channel
Pairing
A-D Convertion Gain Amplifiers
Deserializers
Level Detection
Multiplexer (4 x 4 Router)
Gain and AES Output
Ch 1/2
Ch 3/4
Output Drivers
Bal/Unbal
Switch
Bal/Unbal
Switch
Output Drivers
AES 1
Out
AES 2
Out
Trk In
Trk Out
Genlock T
iming
Generator
Sync Separator
Control and Status Registers
Input 1-4 LEDs
RS232
Tracking
Data I/O
LEDs
LEDs
Microcontroller
8204_01