User's Manual

APPLICANT: MOTOROLA EQUIPMENT TYPE: ABZ89FC4827
User / Operational Manual
Functional Description / Operation of Modules (Draft)
EXHIBIT D1-6
The following table shows the specifications of MTR3000 Power Amplifier (PA).
Specifications of Power Amplifier
Parameter Specification
Operational Frequency Range 403–435 MHz (R1) or 435–470 MHz (R2)
Rated RF Output Power Range 25–100 W
Rated RF Input Power Range 9.8–14 dBm
28.6V Supply Nominal Voltage (AC Power) 28.6V (+/- 4%)
14.2V Supply Nominal Voltage 14.2V (+/- 3%)
28.6V Supply Maximum Current Draw 12.6A
14.2V Supply Maximum Current Draw 2.0A
Functional Theory of Operation
A low-level modulated RF signal (approximately +13 dBm) from the Exciter Module enters the PA Input board via a
coax cable. The signal is input to the IPA and amplified to approximately 0 to 10 W (depending on the dc power
control voltage (V_CNTL) from the PA output board). The IPA output is then fed to the Dual Device Module for
further amplification.
The output of the DDM is then transferred to the circulator and then to the harmonic filter/coupler via the PA output
board. The signal then exits from the Power Amplifier Module via an N-type coax connector.
A single circulator is built into the Power Amplifier Module to provide isolation between the PA module and the
transmit antenna.
A thermistor mounted on the PA printed circuit board outputs a variable resistance proportional to the heat sink
temperature. This signal is fed to the power control circuitry on the PA output board, which monitors the signal and
reduces the PA output power (and enables a fan) if the PA temperature exceeds set limits.
A feedback and control loop configuration is used to regulate the PA output power. The Directional Coupler
generates a dc voltage proportional to the PA Module output power. This voltage is fed to power control circuitry
on the PA output board where it is compared to reference voltages to generate a dc power control voltage. The
Station Control Module sends current and power limit signals to a D/A converter (via the SPI bus) to control the
maximum current/control voltage levels. The control voltage is fed to the IPA module where it controls the IPA
output, thus controlling the overall output from the PA Module.
Analog signals from various strategic operating points throughout the PA module are fed to an A/D converter,
which converts them to a digital signal and, upon request by the Station Control Module, outputs the signal to the
Station Control Module via the SPI bus.
For example, the directional coupler generates a dc voltage proportional to the reflected power. This signal is
converted to a digital signal and sent to the SCM. If the sense line indicates an impedance mismatch (high
VSWR), the PA is either cut back in power or shut down completely.