User's Manual

545C Operations Manual

02/10/2012 Prerelease DCN 00001789-A

3.2 Printed Circuit Board Assemblies

The MCC-545C contains three printed circuit board assemblies as shown

in Figure 2.2.

3.2.1 Microprocessor

The low-power 32-bit microprocessor controller performs the radio

control, 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 for generating the GMSK RF signal.

3.2.2 Transceiver

The selectable-rate transceiver uses a vector phase modulator (+13DBm

output) and frequency synthesizers to produce 9.6 kbps.

3.2.3 Power Amplifier

Note: The nominal RF power amplifier rating of the MCC-545C is 100W

or 50 dBm. The output power is calibrated at the factory at the

expected operating frequency. Measured power values may vary up to 1

dB from rated power, up to 51 dBm or 125W over the frequency range

of the radio.

The multi-stage power amplifier includes a 2 watt, 2-stage preamplifier;

a 100 watt, solid-state, 2-stage power amplifier; and a power switch.

A 12-channel GPS receiver may be mounted on the processor board as

an optional subassembly.

All components are soldered in place using surface mount technology.

As an option, the boards can be conformal coated with an acrylic

encapsulate that contains a tropicalizing, anti-fungal agent to provide

additional protection against moisture and contamination.