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Theory of Operation
3- 2
RSA3303A & RSA3308A Service Manual
Down Converter
The RF3 module contains the 1
st
Converter, 1
st
Local Oscillator, 1
st
IF Amplifi-
er, and other components. After level adjustment in the RF input circuit, the
input signal is applied to the 1
st
Converter. Mixed with 1
st
LO signal, the input
signal is frequency-converted into 1
st
IF signal of 4232 MHz. Oscillation
frequency of 1
st
Local Oscillator is controlled with a synthesizer (RF4 module)
in this case, so that 1
st
IF signal is always maintained at 4232 MHz. After this,
the 1
st
IF signal passes through the 1
st
IF Amplifier that has a gain of approxi-
mately 10 dB, and is sent to the 2
nd
Converter (RF2 module).
In baseband, an input signal enters the 1
st
Converter. Then the signal path is
switched with a relay and the signal is sent directly to the A10 A/D board for
A/D conversion. In RF1 band, an input signal goes through all converters (1
st
,
2
nd
, and 3
rd
). In RF2/3 band, an input signal is directly frequency-converted by
the 1
st
Converter into the 2
nd
IF signal of 422 MHz, then sent directly to 3
rd
Converter, bypassing the 2
nd
Converter.
The RF2 module consists of the 2
nd
Converter, 3
rd
Converter, and 2
nd
Local
Oscillator. The 1
st
IF signal sent from the 1
st
Converter passes through a
Band-pass Filter and a Low-pass Filter for removal of unnecessary frequency
bands. After this, the 1
st
IF signal enters the 2
nd
Converter. In the 2
nd
Converter,
the 1
st
IF signal is mixed with the 2
nd
LO signal and frequency-converted into
the 2
nd
IF signal of 422 MHz. Same with the case of 1
st
Local Oscillator,
frequency of 2
nd
Local Oscillator is controlled with a synthesizer circuit (RF4
module) to stabilize LO output frequency.
The 2
nd
IF signal is sent to the 3
rd
Converter. In the 3
rd
Converter, the signal is
mixed with the 3
rd
LO signal and frequency-converted into the 3
rd
IF signal of
39 MHz. After selected with a band-switching relay located at the input section
of the 3
rd
Converter, the 2
nd
IF signal directly sent from the 1
st
Converter in
RF2/3 band mode is also frequency-converted into the 3
rd
IF signal of 39 MHz.
The RF5 module consists of the 3
rd
IF Gain block, Oscillator block, and 10 MHz
Reference Oscillator. The Oscillator block contains the 3
rd
Local Oscillator and
an oscillator of Sampling Clock signal to be supplied to A/D Converter.
The Gain block consists of a Step Amplifier of 10 dB/step with the maximum
gain of 50 dB and a Step Attenuator with the maximum attenuation of --30 dB.
This block maintains the 3
rd
IF signal to be sent to A/D Converter at an
appropriate level, and adjusts the accuracy of conversion gain.
Both the 3
rd
LO signal and A/D clock signal generated in the Oscillator block are
highly stabilized signals locked with a 10 MHz reference signal, and are output
to the 3
rd
Converter and A10 A/D board, respectively.
RF3 Module
RF2 Module
RF5 Module
Содержание RSA3300A
Страница 4: ......
Страница 12: ...Table of Contents viii RSA3303A RSA3308A Service Manual...
Страница 16: ...Service Safety Summary xii RSA3303A RSA3308A Service Manual...
Страница 20: ...Preface xvi RSA3303A RSA3308A Service Manual...
Страница 22: ...Introduction xviii RSA3303A RSA3308A Service Manual...
Страница 23: ...Specifications...
Страница 24: ......
Страница 43: ...Operating Information...
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Страница 46: ...Operating Information 2 2 RSA3303A RSA3308A Service Manual...
Страница 47: ...Theory of Operation...
Страница 48: ......
Страница 55: ...Performance Verification...
Страница 56: ......
Страница 109: ...Adjustment Procedures...
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Страница 145: ...Maintenance...
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Страница 190: ...Removal and Installation Procedures 6 44 RSA3303A RSA3308A Service Manual Figure 6 21 Mother board removal...
Страница 213: ...Removal and Installation Procedures RSA3303A RSA3308A Service Manual 6 67 Figure 6 32 Rear panel modules...
Страница 214: ...Removal and Installation Procedures 6 68 RSA3303A RSA3308A Service Manual...
Страница 231: ...Options...
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Страница 234: ...Options and Accessories 7 2 RSA3303A RSA3308A Service Manual...
Страница 235: ...Electrical Parts List...
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Страница 238: ...Electrical Parts List 8 2 RSA3303A RSA3308A Service Manual...
Страница 239: ...Diagrams...
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Страница 242: ...Diagrams 9 2 RSA3303A RSA3308A Service Manual...
Страница 249: ...Mechanical Parts List...
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Страница 255: ...Replaceable Parts RSA3303A RSA3308A Service Manual 10 5 1 2 3 4 5 6 7 8 9 10 2 11 12 13 14 Figure 10 1 External modules...
Страница 261: ...Replaceable Parts RSA3303A RSA3308A Service Manual 10 11 1 2 RF4 RF2 RF3 RF5 3 4 5 Figure 10 4 RF modules...
Страница 279: ...Replaceable Parts RSA3303A RSA3308A Service Manual 10 29 1 2 3 4 5 6 7 8 9 10 11 12 Figure 10 13 Chassis modules 2...
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