RoadMAPS Overview
RoadMAPS User’s Manual
2-15
and stored into memory. The receiver processes only signals
received from these MIUs and ignores readings from MIUs on
routes that are not currently being read.
The receiver filters out duplicates in order to keep the best or last
reading received. This optimizes memory storage space. Records
for each reading are stored in the receiver database to eliminate
duplicates and keep track of reading data.
The DMR processes 10 MHz of band with a full 128-channel
receiver, of which only 77 channels are available, and extracts
messages which are sent to the CPU. The DMR will receive and
demoduleat up to eight simultaneous SURF messages and up to
eight simultaneous Itron messages, provided they are not trans-
mitted in the same RF channel. The RoadMAPS Unit together with
the MIU functions as a transmitter/receiver pair that works
together as a spread spectrum system.
In addition to handling these spread spectrum functional require-
ments, the receiver can synchronize with multiple transmitters at
the same time and maintain reliable data transmissions for every
transmitter.
Central Processing Unit (CPU)
The Central Processing Unit (CPU) is based on a PC104 board. It
receives the messages obtained from the band by the DMR mod-
ule through the PC104 (ISA) bus. It then extracts the data and uses
an RS-232 serial link to transfer it to the Portable Personal Com-
puter (PPC). The CPU also uses an RS-232 serial link to program
the RF transmitter with the data received from the PPC.
The CPU will temporarily store received data, and will download a
configuration to the DMR module. It also sets the DMR parame-
ters, automatically tests the DMR board, and resets the parame-
ters.
Содержание RoadMAPS
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