Grass Valley 7600REF - Manual (Page 54)

54 7600 SD/HD/MHD-REF — Instruction Manual
Operation
tenance, or changes in local conditions in which the required signals have
been degraded such that time synchronization is lost.
Acquisition Process
With satisfactory reception, the acquisition process commences automati-
cally and takes around 15 minutes. An enhanced mode (Site Survey) is suit-
able for static installation and may be initiated from the Site Survey
selection on the GPS menu. A complete Site Survey can take around 2
hours. Once completed, it provides more accurate timing signals.
A 1 Pulse Per Second (1PPS) signal waveform is illustrated in
Figure 26. 1PPS Signal Waveform
The leading edge of the 6 ms wide, positive going pulse provides the timing
reference plane for locking external equipment.
Internally, this signal locks the 27MHz PLL Oscillator such that PAL output
signals are both frequency locked and phase locked. Any NTSC output
signals are frequency locked but cannot be phase locked.