GRASS VALLEY Profile XP PVS1000, Service Manual

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Appendix B Theory of operation
162 Profile XP Service Manual 23 July 2004
Real time subsystem
The real time subsystem is responsible for the following functions in the Profile XP
system:
• manages the data flow to and from, and the real time control of, the encoders and
decoders, the video, audio, and time code I/O, and the media storage subsystem.
• executes the low-level device drivers
• manages the Media File System
• executes events on a play time line
Real Time System board
The Real Time System board contains circuitry for three separate functions:
• Real Time Processor
• LTC and GPI I/Os
• Genlock
A second generation of this board is required in the PVS1100 Series, and can be used
for all Profile XP models provided they are running Profile System Software v. 5.0.
Real Time Processor (RTP)
The RTP executes all the real time core software. The RTP controls all of the I/O and
processing modules included in the Real Time Subsystem via communication over
the PCI bus. The RTP communicates with the applications processor over a shared
memory-based inter-processor communications channel which includes the ability to
interrupt and to accept interrupts from the applications processor.
LTC & GPI I/Os
Four linear time code (LTC) inputs and outputs are provided. Vertical interval time
code (VITC) is input from the video reference signal.
The general purpose interface (GPI) port has 8 inputs and 8 outputs, and is intended
for signaling events in a studio environment.
This part of the board also generates the Black and Colorbar signals used for loss of
input or output video conditions (SD only).
Genlock
The Genlock section provides these functions:
• Generation of system clocks for SD (27MHz) and HD (either 37.0879 or 37.125
Mhz)
• Generation of frame reference pulses
• Ability to lock system clocks and frame reference pulses to tri-level sync or to
NTSC/PAL bi-level sync (reference video input).