3-4
Basic Theory of Operation
: Analog Mode of Operation
Figure 3-4. Receiver Block Diagram (700/800 MHz)
3.2.1.1 GPS
The GPS signal is tapped at the antenna port via a series resonant network (diplexer) which provides
a very low capacitive load to the transceiver. The diplexer circuitry provides rejection to radio band
signals up to ~1GHz which serves as isolation between the radio RF and GPS signal paths. The
GPS signal is filtered though a GPS SAW filter - LNA – Saw filter chain before going into the TI GPS
IC for processing.
Figure 3-5. GPS Diagram
3.2.1.2 VHF Front-End
From the 15 dB Step Attenuator, a VHF signal is routed to the first pre-selector filter followed by an
LNA and a second pre-selector filter. Both filters are discrete and tunable designs and are used to
band limit the incoming energy and suppress known spurious responses such as Image and the ½ IF
spur. The output of the second pre-selector filter is applied to the RF port of the Mixer IC. The Mixer
IC is also excited by a Local Oscillator (LO) signal at the LO port to down-convert the RF signal to a
109.65 MHz intermediate frequency (IF). The down converted IF signal is passed through a crystal
filter which drives the input of the Abacus 3 Analog to Digital Converter IC (AD9864).
3.2.1.3 UHF1/UHF2 Front-End
From the 15 dB Step Attenuator, a UHF1/UHF2 signal is routed to the first pre-selector filter followed
by an LNA and a second pre-selector filter. Both filters are discrete and tunable designs and are
used to band limit the incoming energy and suppress known spurious responses such as Image and
the ½ IF spur. The output of the second pre-selector filter is applied to the RF port of the Mixer IC.
The Mixer IC is also excited by a Local Oscillator (LO) signal at the LO port to down-convert the RF
signal to a 109.65 MHz intermediate frequency (IF). The down converted IF signal is passed through
a crystal filter which drives the input of the Abacus 3 Analog to Digital Converter IC (AD9864).
15 dB Step
Attenuator
Antenna
Switch
SW
DIG_CTRL_ATTH
700
800
700
800
Rx LO
IF Filter
Diplexer
SW
SW
SW
SSI
18Mhz
CLK
Abacus III
ABACUS III
Dec.
Filter
ΣΔ
ADC
2nd
LO
LO CLK
To GPS
To Radio transceiver path
GPS IC
GPS Receiver Circuit
Antenna
OMAP
Processor
Diplexer
Содержание APX 4000
Страница 1: ...APXTM TWO WAY RADIOS APX 1000 APX 2000 APX 4000 APX 4000Li BASIC SERVICE MANUAL ...
Страница 6: ...Notes iv Commercial Warranty ...
Страница 8: ...ii Notes ...
Страница 16: ...x Portable Radio Model Numbering System Notes ...
Страница 46: ...3 12 Basic Theory of Operation Controller Section Notes ...
Страница 60: ...5 12 Performance Checks Transmitter Performance Checks Notes ...
Страница 90: ...6 30 Radio Alignment Procedures Performance Testing Figure 6 41 Transmitter Test Pattern Screen 900 MHz ...
Страница 128: ...8 34 Disassembly Reassembly Procedures Ensuring Radio Submergibility Notes ...
Страница 138: ...10 6 Exploded Views and Parts Lists APX 2000 APX 4000 APX 4000Li Back Kit Exploded View Parts List Notes ...
Страница 142: ...Index 4 Index Notes ...
Страница 143: ...Title Page ASTRO APX 1000 Digital Portable Radios Section 2 VHF UHF1 UHF2 700 800 MHz APX 1000 ...
Страница 144: ...ii Notes ...
Страница 150: ...viii List of Figures Notes ...
Страница 152: ...x Portable Radio Model Numbering System Notes ...
Страница 208: ...6 24 Radio Alignment Procedures Performance Testing Figure 6 30 Transmitter Test Pattern Screen 700 800 MHz ...
Страница 240: ...7 32 Disassembly Reassembly Procedures Ensuring Reliable Splash Protection Notes ...
Страница 250: ...9 6 Exploded Views and Parts Lists APX 1000 Back Kit Exploded View Parts List Notes ...
Страница 254: ...Index 4 Index Notes ...
Страница 255: ...Title Page ASTRO APX 1000 Digital Portable Radios Section 3 900 MHz APX 1000 ...
Страница 256: ......
Страница 262: ...viii List of Figures Notes ...
Страница 264: ...x Portable Radio Model Numbering System Notes ...
Страница 278: ...3 8 Basic Theory of Operation Controller Section Notes ...
Страница 336: ...7 32 Disassembly Reassembly Procedures Ensuring Reliable Splash Protection Notes ...
Страница 346: ...9 6 Exploded Views and Parts Lists APX 1000 Back Kit Exploded View Parts List Notes ...
Страница 350: ...Index 4 Index Notes ...
Страница 351: ...Title Page ASTRO APX APX 2000 APX 4000 Digital Portable Radios Section 4 APX 2000 APX 4000 Two Knobs ...
Страница 352: ...ii Notes ...
Страница 360: ...x Portable Radio Model Numbering System Notes ...
Страница 400: ...5 12 Performance Checks Transmitter Performance Checks Notes ...
Страница 427: ...Radio Alignment Procedures Performance Testing 6 27 Figure 6 34 Transmitter Test Pattern Screen 700 800 MHz ...
Страница 428: ...6 28 Radio Alignment Procedures Performance Testing Notes ...
Страница 434: ...7 6 Encryption Erase an Encryption Key Notes ...
Страница 478: ...8 44 Disassembly Reassembly Procedures Ensuring Radio Submergibility Notes ...
Страница 488: ...10 6 Exploded Views and Parts Lists APX 2000 APX 4000 Two Knobs Back Kit Exploded View Parts List Notes ...
Страница 489: ...Title Page ASTRO APX 1000 APX 2000 APX 4000 APX 4000 Li Digital Portable Radios Section 5 Appendices ...
Страница 490: ...ii Notes ...
Страница 492: ...A 2 Accessories Notes ...
Страница 496: ...Notes B 4 EMEA Warranty Service and Technical Support Further Assistance From Motorola ...
Страница 500: ...C 4 LACR Replacement Parts Ordering and Motorola Service Centers Motorola Service Centers Notes ...
Страница 520: ...Glossary 12 Glossary Notes ...
Страница 524: ...Index 4 Index Notes ...
Страница 525: ......