Figure 3-2. Transceiver (Uhf1/ Uhf2) Block Diagram (Power And Control Omitted) - Motorola APX 3000 Detailed Service Manual

Theory of Operation: Main Board
3.1 Main Board
The main board performs the transmitter and receiver functions necessary to translate between
voice and data to modulated radio-frequency (RF) carrier at the antenna. The main board contains
all the radio's RF circuits for the following major components:
• Receiver
• Transmitter
• Frequency Generation Unit (FGU)
• Controller
Figure 3-2, Figure 3-3
block diagrams.
GPS
Rev
Power
Detector
*
LNA
UHF1/ UHF2

Figure 3-2. Transceiver (UHF1/ UHF2) Block Diagram (Power and Control Omitted)

and Figure 3-4
Log
Amp
Harmonic
Filter
Digital
RF Atten
coupler
15dB Step Attn
16.8MHz
TRIDENT IC
PRESCALAR
BUFFER
16.8MHz
BUFFER
UHF1/ UHF2
illustrates the UHF1, UHF2, VHF and 700/800 MHz transceiver
Antenna Switch
FET
LOOP
RX VCO
FILTER
PRE
TX VCO
BUFFER
IF Filter
Mixer
Indicates Sub-shield
Driver
Amplifier
*
TX
TX
BUFFER
TX LO
RX
RX SSI Data
Abacus
RX SSI Frame Sync
2nd
LO
3-3
FGU
Transmitter
Receiver
RX SSI Clock