Thales NSS 100S-1 Component Maintenance Manual With Illustrated Parts List page 69

COMPONENT MAINTENANCE MANUAL
C17004
F. Operation of sub-unit Clock PCB Z5
This PCB is designed to generate a reference clock: 10 MHz.
This clock is generated by a thermostated oscillator Y1 (temperature adjust-
ment at + 85°C); Y1 is powered by regulator Q1 which supplies - 12 V, from
-15VPILOTE from HF PCB Z4.
The cold point of oscillator Y1 is closed off from the analog ground due to
a 0.5 ohm resistor installed on HF PCB Z4, thus enabling monitoring of IPI-
LOTE current discharged by Y1: the value of IPILOTE, increased at start-up,
is stabilized whenever the temperature of Y1 is adjusted.
IPILOTE is matched in Z4, informing the CPU that Y1's temperature has been
set which, by extension, means that the clock is stable.
Z5
Z4
HF PCB CLOCK PCB
-12V
Régulator
-15VPILOTE
Q1
Thermostated
10MHZ
oscillator
(Z4)
Y1
IPILOTE
Monitoring
34-57-96
Page 43
MAY 30/95
COPYRIGHT SEXTANT Avionique 1995
c
The document reference is online, please check the correspondence between the online documentation and the printed version.