Ross SRG-4400, User Manual

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5–34 • Menu System SRG-4400 User Manual (Iss. 06)
Genlock Menus
The SRG-4400 has a very stable 10MHz internal oscillator. The SRG-4400 can free-run on this
10MHz reference and maintain long term stability.
Alternatively, the SRG-4400 can Genlock to an NTSC, or PAL B/G video reference. In this mode,
the long term stability is defined by the external reference.
In a third mode the SRG-4400 can frequency lock to a reference from an external oscillator.
Again, in this mode, the long term stability is defined by the external oscillator.
In a fourth mode, the SRG-4400 can Genlock to a reference from GPS, with the 10MHz internal
oscillator being disciplined by the GPS system.
When locked to a Composite video signal, the lock will be frequency and phase related. When
locked to an external oscillator, the lock will be frequency related only.
When locking to GPS, the lock mode can be selected from the following options:
• Time lock
• Time and Frequency lock
• Time and Frequency and Phase lock
Genlocking to an External Video Reference
The SRG-4400 Genlock to an external video reference in the following manner. As soon as a
video reference is applied, it is evaluated, usually within 2 seconds, and, if valid, the Genlock
system performs an initial “quick-lock” to quickly achieve field and line lock. Then, a
“slow-lock” is performed in order to achieve sub-carrier lock, and ultimately Sc-H lock. Both of
these lock modes are designed to “glide” the SRG-4400 video output(s) smoothly towards the
required lock point.
For situations where the reference and the SPG output are quite close to each other timing-wise,
this Genlocking process may happen quite quickly, within a few seconds or so. At other times,
especially when a PAL reference is four fields removed from the required lock point, the process
to complete the full Genlock process may take as long as 15 seconds.