Motorola GTR 8000, Manual

Page: 63 / 346

2.1.1.2.1 Exciter
2.1.1.2.1 Exciter
The exciter on the XCVR RF board provides the transmitter functions for the base radio. The exciter circuitry
generates a low-level, modulated RF signal that passes to the power amplifier. It supports various modulation types
as well as bandwidths up to 25 kHz, through software programming.
The exciter also provides a controlled output power level to the power amplifier.
The Exciter is present in a GPW 8000 Receiver but, is powered down to save energy.
2.1.1.2.2 Receiver
The receiver provides either single receiver input or dual (HPD or TDMA) receiver inputs for dual diversity. The
receiver also provides enhanced diagnostic capabilities using an on board noise source generator. It includes
a wide tuning range (electronic varactor-tuned) preselector. The preselector is electronically tuned to the desired
receive frequency anywhere between 792–825 MHz, UHF R1 380–435 MHz, UHF R2 435–524 MHz, or VHF
136–174 MHz.
2.1.1.3 Transceiver External Interfaces
The transceiver external interfaces include seven external ports, a switch and LEDs. If a transceiver option card is
part of the transceiver, there are four additional external ports. See
3.4.7 Connections – Front, page 3-27 for the
port connections. See 10.1 LEDs, page 10-1 for information on the LEDs.
2.1.1.3.1 Transceiver Switch
There is one multifunction Reset switch on the front of the transceiver module, accessible through the drop-down
door to the left of the fans. The Reset switch has two functions:
Figure 2-3 Transceiver Reset Switch (viewable through drop-down door)
Table 2-1 Transceiver Front Reset Switch Functions
User Action Result
Press switch for less than 1 second Service Mode (LED 3 lights amber)
Press switch for more than 3 seconds Transceiver Control Module Reset
6871022P86-A - November 2012 2-3