Operations Manual

DESCRIPTION 2-3
O&M of the MCC-545B PACKET DATA RADIO
12/2000
used in dispatch centers, corporate/district offices, and other monitoring Stations for updating
map displays or additional functions. Refer to Appendix B for a description of the GPS
commands.
2.5 Maintenance Features
An operator terminal or a remote command from a distant unit can also be used to read and
display the 545B's status such as radio propagation channel statistics, battery voltage during
transmission (loaded), battery voltage when not transmitting (unloaded), RF forward and
reflected power (checks antenna), and receiver noise levels. It can also be used to display and
configure the 545B's operating characteristics, as detailed in Chapter 4.
An internal Li ion battery is used to maintain the internal real time clock and battery backed
RAM. This battery is capable of operating the clock in a power down state for a period of
approximately 6 months. This battery should be removed if the unit is stored without power for
extended periods of time.
2.6 Hardware Organization and Layout
The unit contains five printed circuit assemblies:
A 100 watt all solid-state 2 stage power amplifier.
A 2 watt 2 stage preamplifier and power switch.
A BPSK 4 KB/sec transceiver containing a BPSK receiver, vector phase modulator (+13Dbm
output) and three frequency synthesizers.
A low-power microprocessor controller used to perform radio control and link and network
protocol functions. This assembly also contains a digital signal processor (DSP)and
digital to analog converter (DAC)for generating the in-phase (I) and quadrature-phase
(Q) base band signals required to generate the BPSK RF signal.
An 8 channel GPS receiver (optional)
The following paragraphs contain a brief description of each of the five main hardware elements
in the 545B. Figure 2.2 presents a block diagram for the 545B. Figure 2.3 presents an outline
drawing showing mounting holes, connectors, and dimensions.