Grass Valley 8941 - Manual (Page 19)

8941 Instruction Manual 19
Functional Description
Functional Description
Refer to the simplified block diagram in Figure 9 while reading the fol-
lowing functional description.
Figure 9. 8941 Simplified Block Diagram
The Deserializer block equalizes and reclocks the input serial digital video
before going to the Digital Video Output. It generates an 27 MHz clock, and
it also monitors how much of the equalizers gain is used.
Parallel D1 from the Deserializer is routed to the Video Data Extraction
block where horizontal and vertical timing information is extracted and
ancillary and audio data is detected. If ancillary data or audio data is
detected, an LED will light.
The Video Data Extraction and Rounding block also provide the clock for
the Microcontroller. It monitors the video for missing EAV (End of Active
Video) or SAV (Start of Active Video) flags. If EAV or SAV are missing, an
error signal is sent to the Microcontroller block. The input video is either
rounded or truncated (at the user’s option) to eight bits before being passed
on to the Encoder.
The Encoder and D to A block separates the color difference components
from the luminance, and then the signals are separately filtered. The result
is added to the luminance component to form the encoded composite
output signal. Externally generated timing of H and V are input from the
Video Data Extraction and Rounding block to synchronize the Encoder.
Serial
Input Digital
Video
Outputs
8
Deserializer
Digital Video
Output
Analog LPF &
Output Drive
Video Data
Extraction &
Rounding
Module
Health
Power Supply
Monitoring
Module
Health
Alarm
Microcontroller
Encoder
&
D to A 10
Switching
Regulator
+12V
DIP
Switch
RS-232
Test Rx1
Max EQ LED
Audio Detect LED
ANC Data Detect LED
Video Present LEDs
RS-232
Test Tx1
Analog
Video
Outputs
8109_01