Symmetricom ET6000, User Manual

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OPTION DESCRIPTIONS
GPS OPTION 40A GPS OPTION MOTHERBOARD
ASSEMBLY 35007-1
GPS OPTION 40AP W/1 BNC OUTPUT
1.0 INTRODUCTION
GPS Option 40A (GPS Motherboard Assembly 35007-1) provides the expansion capability to
add optional assemblies to the GPS Timing Unit. It provides a platform to support these
assemblies and an interface between these assemblies and the GPS Main Assembly 35002.
The motherboard assembly can support two double width options or four single width options.
Also, depending upon the options themselves, and if space permits, some options can be stacked
on top of other options.
The motherboard is also provided with a variety of rear panel butch plates and output connectors
depending upon the option supplied.
GPS Option 40AP is identical to 40A except that 40AP includes the 812363-9 cable used to
connect J2 of the 35007 Motherboard Assembly to J1 of the 55189 Power Entry and Alarm
Relays Assembly. It provides the signal paths to and from the 55189 Assembly to the GPS Main
Assembly 35002.
1.1 OPERATIONAL FEATURES
The basic motherboard has four plug-in option areas, J7/J9, J8/J10, J18/J22, and J19/J23. Each
of these option areas provides one or two single-ended BNC outputs. However, depending upon
the option installed, some of these outputs may or may not be used.
In this particular configuration, the output connector(s) for the optional assembly plugged into
the J8/J10 and J7/J9 areas of the motherboard require excessive rear panel space. This requires
removing motherboard BNCs J3A through J3E. The only remaining option area with access to a
rear panel BNC is J19/J23.
The following is the correlation between the option area and the output.
J19/J23 Rear
Panel BNC J3F.
The above output is provided via a 250 milliamphere high speed buffer/driver. The gain of the
buffer is 1:1 so the output amplitude is dependant upon the input and the load.
Symmetricom Inc ET6xxx ExacTime GPS TC & FG (Rev C) C-75