OPTION DESCRIPTIONS
GPS OPTION 21A 10 MHZ SINE WAVE SHAPER
ASSEMBLY 20457-45
1.0 INTRODUCTION
This Option Description provides specifications, an explanation of the Sine Wave Shaper logic
used to develop the Sine Wave output and adjustment of the output amplitude.
This Shaper Assembly can be plugged into the J7/J9, J8/J10, J18/J22, or J19/J23 area of the
35007 Motherboard Assembly. The 10MHz Sine Wave output will be present on the rear panel
BNC, J3A, J3B, J3D, or J3E respectively.
1.1 SPECIFICATIONS
The following specifications apply at 13dbm output level using an oven oscillator. These
specifications are worst case.
Harmonics: -35 dBc
Spurious Noise: -35 dBc
Phase Noise:
1Hz -72 dBc/Hz
10Hz -94 dBc/Hz
100Hz -112 dBc/Hz
1KHz -115 dBc/Hz
10KHz -117 dBc/Hz
100KHz -121 dBc/Hz
1.2 FUNCTIONAL EXPLANATION
A 10MHz square wave derived from the 10MHz internal oscillator is input to J1 pin 9 of the Sine
Wave Shaper Assembly. The signal is filtered and shaped to generate the 10MHz Sine Wave
output at P1 pin 2 of the same assembly.
This signal is then routed to a rear panel BNC. Refer to the GPS Option/Connector
Configuration sheet in the User’s Guide for the output connector designation. Refer to the Top
Assembly Drawing for connector location. This signal is adjustable from zero to six volts peak-
to-peak and has been factory adjusted to three volts peak-to-peak into a 50Ω load.
1.3 OUTPUT AMPLITUDE ADJUSTMENT
The output amplitude of this signal can be adjusted to the desired amplitude using LEVEL
potentiometer R13, on the Sine Wave Shaper assembly.
Symmetricom Inc ET6xxx ExacTime GPS TC & FG (Rev C) C-47