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Service Manual
6. UHF1 (400-470 MHz) Information
31
6.2 Receiver Circuit
The receiver circuit is mainly composed of RF band-pass filter, low-noise amplifier, mixer, IF
filter, IF amplifier, and IF processor.
Low-Noise Amp
Band-Pass Filter
Mixer
IF Filter
IF Processor
AD9864
IF Amp
TV/APC
To DSP (OMAP)
TX/RX Switch
Low-Pass Filter
Band-Pass Filter
FLo
RF
IF
Antenna
TX
ADC
Second
Lo VCO
Synthesizer
19.2 MHz
Reference Clock
-16 dB
Attenuation
Q6002
Low-Pass Filter
D6002
Q6003,Q6004
U6002
U6001
Decimation
Filter
FLO Amp
Q6001
Pi Attenuator
Figure 6-2 Diagram of Receiver Circuit
6.2.1 Receiver Front-End
The HF signal from the low-pass filter passes through the first-level band-pass filter, to
remove out-of-band interference signal and to send wanted band-pass signal to the low-noise
amplifier (Q6002). The amplified signal goes to the second-level band-pass filter, to remove
out-of-band interference signal generated during amplification, and to send wanted HF signal
to the mixer (D6002). In the mixer, the wanted signal and the first LO signal are mixed to
generate the first IF signal (73.35 MHz). Then the signal passes through a
π-shaped
attenuator and the LC, to suppress carrier other than the first IF signal, and to increase the
isolation between the mixer and the IF filter. After that, the first IF signal is processed by the
crystal filter (U6001), and is sent to the two-stage IF amplifier circuit (composed of Q6003 and
Q6004) for amplification. Then the amplified signal goes to the IF processor AD9864 (U6002)
for processing.
Summary of Contents for RDR9000
Page 1: ...RDR9000U V Service Manual ...
Page 45: ...Service Manual 6 UHF1 400 470 MHz Information 35 6 4 PCB View PCB View Main Board Top Layer ...
Page 46: ...Service Manual 6 UHF1 400 470 MHz Information 36 PCB View Main Board Bottom Layer ...
Page 48: ...Service Manual 6 UHF1 400 470 MHz Information 38 PCB View Rear Board Top Layer ...
Page 146: ...Service Manual 7 UHF3 350 400 MHz Information 136 7 4 PCB View PCB View Main Board Top Layer ...
Page 147: ...Service Manual 7 UHF3 350 400 MHz Information 137 PCB View Main Board Bottom Layer ...
Page 149: ...Service Manual 7 UHF3 350 400 MHz Information 139 PCB View Rear Board Top Layer ...
Page 248: ...Service Manual 8 VHF 136 174 MHz Information 238 8 4 PCB View PCB View Main Board Top Layer ...
Page 249: ...Service Manual 8 VHF 136 174 MHz Information 239 PCB View Main Board Bottom Layer ...
Page 251: ...Service Manual 8 VHF 136 174 MHz Information 241 PCB View Rear Board Top Layer ...
Page 346: ...Service Manual 11 Packing Guide 336 11 Packing Guide Figure 11 1Packing Guide ...
Page 352: ...342 ...