3-6
Theory of Operation:
Main Board
3.1.1.2 Power Conditioning Components
DC power-conditioning components include zener diodes, capacitors, ferrite beads, a power
inductor, and the fuse. Diodes VR200 and VR101 provide over-voltage protection. Ferrite beads
(designated E, etc.) and capacitors suppress electromagnetic interference from the main board.
The power-line filter consisting of L200, C202, and C203 suppresses digital noise from the controller
board switching power supplies that could degrade the transmitter spectral purity.
Ground clips M103, M104 and M105 make contact between the main board ground and the radio
chassis. The chassis connection is a necessary electrical reference point to complete the antenna
circuit path. Shields SH1 through SH17 appear on the schematic to show their connection to ground.
3.1.2
Receiver
The RF signal is received at the antenna and is routed through the Harmonic Filter, followed by the
Antenna Switch and the 15dB Step Attenuator IC. The latter contains a switchable attenuator that is
enabled at predetermined RF power thresholds present at the antenna port. The output of the
attenuator leads to the receiver front end section.
• UHF1/ UHF2 band (
See Figure 3-5.
/
See Figure 3-6.
)
• VHF band (
See Figure 3-7.
)
• 700/800 MHz band (
See Figure 3-8.
)
Figure 3-5. Receiver Block Diagram (UHF1)
Antenna
Switch
15 dB Step
Attenuator
UHF
UHF
IF Filter
DIG_CTRL_ATTH
Rx LO
To GPS
Diplexer
SSI
18Mhz
CLK
Abacus III
ABACUS III
Dec.
Filter
ΣΔ
ADC
2nd
LO
LO
CLK
Harmonic
Filter
Содержание Astro APX 3000
Страница 1: ...APXTM TWO WAY RADIOS APX 3000 DETAILED SERVICE MANUAL ...
Страница 2: ......
Страница 4: ...Notes ...
Страница 6: ...vi Document History Notes ...
Страница 10: ...x Table of Contents Notes ...
Страница 12: ...xii List of Tables Notes ...
Страница 18: ...xviii List of Figures Notes ...
Страница 22: ...xxii CommercialWarranty Notes ...
Страница 46: ...3 20 Theory of Operation Main Board Notes ...
Страница 84: ...3 58 Theory of Operation Bluetooth Notes ...
Страница 147: ...Troubleshooting Waveforms Clocks 6 3 6 2 2 4 MHz Clock Trace 1 Trace recorded at R6113 Figure 6 2 4 MHz Clock Waveform ...
Страница 154: ...6 10 Troubleshooting Waveforms Audio SSI 6 3 4 BCLK Trace 1 Trace recorded at R6107 Figure 6 9 Audio SSI BCLK Waveform ...
Страница 156: ...6 12 Troubleshooting Waveforms RX SSI 6 4 2 DA Trace 1 Trace recorded at R2805 Figure 6 11 RX SSI DA Waveform ...
Страница 157: ...Troubleshooting Waveforms RX SSI 6 13 6 4 3 FSYNC Trace 1 Trace recorded at R2804 Figure 6 12 RX SSI FSync Waveform ...
Страница 159: ...Troubleshooting Waveforms TX SSI 6 15 6 5 2 DA Trace 1 Trace recorded at R2817 Figure 6 14 TX SSI DA Waveform ...
Страница 160: ...6 16 Troubleshooting Waveforms TX SSI 6 5 3 FSYNC Trace 1 Trace recorded at R2807 Figure 6 15 TX SSI FSync Waveform ...
Страница 161: ...Troubleshooting Waveforms SPI 6 17 6 6 SPI 6 6 1 CLK Trace 1 Trace recorded at R2803 Figure 6 16 SPI CLK Waveform ...
Страница 162: ...6 18 Troubleshooting Waveforms SPI 6 6 2 CS Trace 1 Trace recorded at R6602 Figure 6 17 CS Waveform ...
Страница 164: ...6 20 Troubleshooting Waveforms I2C BUS 6 7 2 SCL 5V Trace 1 Trace recorded at R2204 Figure 6 19 I2C Bus SCA 5V Waveform ...
Страница 165: ...Troubleshooting Waveforms I2C BUS 6 21 6 7 3 SDA Trace 1 Trace recorded at R6209 Figure 6 20 I2C Bus SDA Waveform ...
Страница 169: ...Troubleshooting Waveforms USB 6 25 6 10 USB 6 10 1 D Trace 1 Trace recorded at TP F_GCAI_USB Figure 6 24 USB D Waveform ...
Страница 170: ...6 26 Troubleshooting Waveforms USB 6 10 2 D Trace 1 Trace recorded at TP F_GCAI_USB Figure 6 25 USB D Waveform ...
Страница 172: ...6 28 Troubleshooting Waveforms SDRAM 6 11 2 CLKX Trace 1 Trace recorded at TP6308 Figure 6 27 SDRAM CLKX Waveform ...
Страница 208: ...6 64 Troubleshooting Waveforms LF CW on Spectrum Analyzer Notes ...
Страница 222: ...7 14 Troubleshooting Tables List of Board and IC Signals Notes ...
Страница 282: ...8 60 Schematics Boards Overlays and Parts Lists Main Board Block UHF1 84012513001_A Notes ...
Страница 338: ...8 116 Schematics Boards Overlays and Parts Lists Main Board Block 700 800 MHz 84012501002 Notes ...
Страница 390: ...8 168 Schematics Boards Overlays and Parts Lists Main Board Block VHF 84012512001_A Notes ...
Страница 456: ...9 8 Debugging Fixture Powering up Covert Board Notes ...
Страница 468: ...Glossary 10 Glossary Notes ...
Страница 472: ...Index 4 Index Notes ...
Страница 473: ......