Chapter 3 ______________________________________________________ Functional Description
VAISALA ________________________________________________________________________ 9
CHAPTER 3
FUNCTIONAL DESCRIPTION
This chapter covers the connections and operation of MRG112.
GPS Module and Connections
The GPS module is an independent GPS receiver for local channel
L1-band GPS signals. The module is installed on the main board of
the MRG112.
The local signal is connected from local GPS antenna to the module
via the front panel Local Ant. connector (X4) by using coaxial
cabling. The current limited supply v4.8 V is connected via
the Module to the Low-Noise-Amplifier of the Local Antenna. The
RF signal and the supply voltage share the same path.
The GPS module has two serial communication channels (A and B).
The channel A is used for communication with the Control Processor
and to send GPS data. Channel A (TXD1M, RXD1M) is connected to
the system connector X1 via line switch A2. Channel B can be used to
connect external data sources directly to the Module. Channel B
(TXD2, RXD2M) is connected to the front panel connector COM1
and to the system connector. The output signal TXD2 is connected to
the front panel and to the system connector in parallel. The input
signals RXD2A and RXD2B are connected via logical OR connection
in PLD D1 to the GPS Module.
The reset input MANRES# is provided for full initialization of the
Module. The signal is controlled by PLD D1 and it is activated when
MRES# (X1/c37) is active low or output A1/2 is active high.
The time reference output signal 1PPS (one-pulse-per-second ) is
provided by the Module. The signal has one-second period and its
