Symmetricom ET6000, User Manual

Page: 122 / 206

APPENDIX C
OPTION DESCRIPTIONS
GPS OPTION 01/01A THREE CHANNEL ENCODER
ASSEMBLY 55116
1.0 INTRODUCTION
This Option description provides a functional explanation of the Three Channel Encoder which
can be installed inside the ExacTime unit.
Option 01 describes the modulated serial time code output code selection, specifications and
adjustments. Option 01A describes the optional DC serial code output specifications.
1.1 FUNCTIONAL EXPLANATION
The ExacTime GPS Time Code and Frequency Generator has the capability of generating three
modulated time code outputs on rear panel BNC connectors J3a, J3b, J3c, J3d, J3e or J3f. For the
specific connections used, refer to the GPS Option/Connector Configuration sheet in the front of
the ExacTime User’s Guide. Each of these connectors can output any of the following codes:
IRIG A132 IRIG B122 IRIG G142 IRIG E112 IRIG E122
IRIG H112 IRIG H122 XR3 2137 NASA 36
These modulated codes are generated using the Three Channel Encoder, Assembly 55116. Code
type selection is remotely selected via the RS-232 I/O Port, rear panel connector J12 or via the
front panel keypad. SW4 located on Assembly 55116 (plugged into the option area of the
Synchronized Time Code/Frequency Module) must have the jumper block shorting the pins.
For the optional DC Code Output, Option 01A, connectors see the GPS Option/Connector
Configuration sheet in the ExacTime User’s Guide.
1.2 OUTPUT SPECIFICATIONS
Note: Changing the Code Output selection may change the output amplitude. See Table 01-2
for amplitude and modulation ratio controls.
1.2.1 OUTPUT AMPLITUDE (MODULATED)
Nominal 3 volts peak-to-peak into a 50
Ω
load (adjustable)
1.2.2 MODULATION RATIO
Nominal 3:1, adjustable from 2:1 to 6:1
Symmetricom Inc ET6xxx ExacTime GPS TC & FG (Rev C) C-1