
3-8
Basic Theory of Operation
: Analog Mode of Operation
3.2.2.2 UHF1/UHF2 Transmit
Once a UHF frequency for transmit has been selected, the Trident IC and the accompanying logic
circuitry will enable the voltage controlled oscillator which then generates the desired transmit
frequency. This transmit signal is then routed to the TX buffer amplifier which amplifies the signal.
The signal is routed to the UHF1/UHF2 Driver amplifier and then to the discrete final power amplifier.
The signal now goes through the antenna switch which routes the power to the harmonic filter which
will filter out the harmonics of the carrier signal and then passes through a directional coupler. The
Log Amp power detector Monitors the output of the directional coupler and adjusts the control
voltages to the driver amplifier and final power amplifier. Finally, the RF signal is routed to the main
antenna.
3.2.2.3 700/800 MHz Transmit
Once a 700/800 MHz frequency for transmit has been selected, the Trident IC and accompanying
logic circuitry enable the correct voltage controlled oscillator which then generates the desired
transmit frequency. This transmit signal is then routed to the TX buffer amplifier which amplifies the
signal. The signal is routed to the 7800 Driver amplifier and then to the discrete final power amplifier.
The signal now goes through the antenna switch which routes the power to the harmonic filter which
will filter out the harmonics of the carrier signal and then passes through a directional coupler. The
Log Amp power detector Monitors the output of the directional coupler and adjusts the control
voltages to the driver amplifier and the discrete final power amplifier. Finally, the RF signal is routed
to the main antenna.
3.2.2.4 900 MHz Transmit
Once a 900 MHz frequency for transmit has been selected, the Trident IC and accompanying logic
circuitry enable the correct voltage controlled oscillator which then generates the desired transmit
frequency. This transmit signal is then routed to the TX buffer amplifier which amplifies the signal.
The signal is routed to the 900 MHz Driver amplifier and then to the discrete final power amplifier.
The signal now goes through the antenna switch which routes the power to the harmonic filter which
will filter out the harmonics of the carrier signal and then passes through a directional coupler. The
Log Amp power detector Monitors the output of the directional coupler and adjusts the control
voltages to the driver amplifier and the discrete final power amplifier. Finally, the RF signal is routed
to the main antenna.
Summary of Contents for APX 4000
Page 1: ...APXTM TWO WAY RADIOS APX 1000 APX 2000 APX 4000 APX 4000Li BASIC SERVICE MANUAL ...
Page 6: ...Notes iv Commercial Warranty ...
Page 8: ...ii Notes ...
Page 16: ...x Portable Radio Model Numbering System Notes ...
Page 46: ...3 12 Basic Theory of Operation Controller Section Notes ...
Page 60: ...5 12 Performance Checks Transmitter Performance Checks Notes ...
Page 128: ...8 34 Disassembly Reassembly Procedures Ensuring Radio Submergibility Notes ...
Page 142: ...Index 4 Index Notes ...
Page 144: ...ii Notes ...
Page 150: ...viii List of Figures Notes ...
Page 152: ...x Portable Radio Model Numbering System Notes ...
Page 240: ...7 32 Disassembly Reassembly Procedures Ensuring Reliable Splash Protection Notes ...
Page 250: ...9 6 Exploded Views and Parts Lists APX 1000 Back Kit Exploded View Parts List Notes ...
Page 254: ...Index 4 Index Notes ...
Page 255: ...Title Page ASTRO APX 1000 Digital Portable Radios Section 3 900 MHz APX 1000 ...
Page 256: ......
Page 262: ...viii List of Figures Notes ...
Page 264: ...x Portable Radio Model Numbering System Notes ...
Page 278: ...3 8 Basic Theory of Operation Controller Section Notes ...
Page 336: ...7 32 Disassembly Reassembly Procedures Ensuring Reliable Splash Protection Notes ...
Page 346: ...9 6 Exploded Views and Parts Lists APX 1000 Back Kit Exploded View Parts List Notes ...
Page 350: ...Index 4 Index Notes ...
Page 352: ...ii Notes ...
Page 360: ...x Portable Radio Model Numbering System Notes ...
Page 400: ...5 12 Performance Checks Transmitter Performance Checks Notes ...
Page 428: ...6 28 Radio Alignment Procedures Performance Testing Notes ...
Page 434: ...7 6 Encryption Erase an Encryption Key Notes ...
Page 478: ...8 44 Disassembly Reassembly Procedures Ensuring Radio Submergibility Notes ...
Page 490: ...ii Notes ...
Page 492: ...A 2 Accessories Notes ...
Page 496: ...Notes B 4 EMEA Warranty Service and Technical Support Further Assistance From Motorola ...
Page 520: ...Glossary 12 Glossary Notes ...
Page 524: ...Index 4 Index Notes ...
Page 525: ......