User Manual

System Description RF-Baton! Transmitter Controller Installation and Operation
2-14 6880497G01-B June 1999
Reference Module with GPS Receiver Option
The Reference Module includes the Ultra High Stability Oscillator (UHSO) and the optional
Motorola OncoreVP GPS receiver (see Figure 2-7).
Figure 2-7: RF-B! Reference Module Block Diagram
UHSO
The 16.8-MHz timing clock is synchronized to a 10-MHz reference provided by a UHSO on
the reference module. This same reference is used by the transmitter to synchronize the
Internal transmit clocks. Using GPS 1PPS as a reference, the host processor sends a UHSO
adjustment value through the SPI Interface to maintain the accuracy of the 10-MHz reference.
GPS Receiver
The optional GPS receiver, also located on the reference module, detects signals from the U.S.
Department of Defense NAV STAR GPS satellites. The GPS receiver uses these signals to
supply timing information and a 1PPS signal to the transmitter and any co-located RF-A!
receivers.
Buffer Amp
& Splitter
10 MHz Osc DA
SPI Circuitry
RS485
Conversion
GPS Receiver
Module
Power
Regulation &
Filter
+5V Filtered
12V Filtered
10V
10 MHz
Output
RXD
TXD
1PPS
GPS Antenna
+5V
12V
RXD TXD 1PPS
302SRH-54
Chip Enable
Address
SPI Bus
Chip Enable
Internal
16.8 MHz
Reference