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Chapter 1, Introduction
Theory of Operation
N:\mkt\MANUALS\HP8924C\ALR\intro.fb
The Receive DSP assemblies analyze the 3.6864 MHz signal to make IQ
modulation measurements, such as Rho, Timing Accuracy, Carrier Feedthrough,
and Phase Error.
Figure 4
Analyzing CDMA Signals
RF Signal
Generation
The Signal Generator Synthesizer (A24) assembly creates a 500-1000 MHz
signal. The reference signal for the synthesizer is supplied by the Reference (A27)
assembly. The synthesizer’s frequency is varied using a divider network in the
feedback circuit of the phase locked loop. Any FM modulation signal (from the
Modulation Distribution (A34) assembly), and the frequency sweep signal for the
Spectrum Analyzer and Tracking Generator, are integrated into this feedback
loop. If a CDMA signal is not being generated, the 500-1000 MHz signal is
passed through the I/Q Modulator (A25) assembly, bypassing the I/Q modulator.
IQ Modulation
If a CDMA signal is being generated, the signal is I/Q modulated in the I/Q
Modulator assembly, using data from the Cell Site Analog (A8) assembly. The
Cell Site Analog assembly gets its data from the two Cell Site Digital (A7 & A9)
assemblies, which are controlled by the Protocol Processor (A6) assembly. Up to
eight code channels of CDMA modulation data and noise may be summed into the
IQ modulator at one time. These channels provide phone paging, synchronization,
voice (traffic) transmission, and other CDMA system functions.
Final Frequency
Conversion and
Leveling
The Output (A26) assembly performs three tasks:
•
Mixes or divides the 500-1000 MHz signal to produce signals below 500 MHz (down
to 0.4 MHz). A 1 GHz LO from the Reference (A27) assembly is used for mixing.
•
Provides AM modulation (when selected).
114.3MHz IF
from Receiver
LO/IF Demod Assembly (A31)
117.9864 MHz
3.6864 MHz
IQ
Demodulator
I data
Q data
To Spectrum Analyzer (A32)
Cell Site Digital Assemblies
IF Gain Control
Protocol
Processor (A6
Call Setup and
Control
IQ Decoding and CDMA Generator
Data Coding
Receive/Opt. DSP Assemblies (A11,A12
CDMA IQ Modulation
Measurements
(A7,A9)
Содержание 8924E
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Страница 53: ...Contents 53 N mkt MANUALS HP8924C ALR 8924CE TOC Index 633 ...
Страница 54: ...Contents 54 N mkt MANUALS HP8924C ALR 8924CE TOC ...
Страница 70: ...70 Chapter 1 Introduction Hardware and Firmware Enhancements N mkt MANUALS HP8924C ALR intro fb ...
Страница 137: ...137 N mkt MANUALS HP8924C ALR per_adj fb 4 Periodic Adjustments ...
Страница 448: ...448 Chapter 9 HP 8924C E Specifications General Specifications N mkt MANUALS HP8924C ALR specs fb ...
Страница 449: ...449 N mkt MANUALS HP8924C ALR service fb 10 Service Screen ...
Страница 454: ...454 Chapter 10 Service Screen Troubleshooting with the Service Screen N mkt MANUALS HP8924C ALR service fb ...
Страница 455: ...455 N mkt MANUALS HP8924C ALR blkdia fb 11 Block Diagrams ...
Страница 522: ...522 Chapter 11 Block Diagrams Assembly Details N mkt MANUALS HP8924C ALR blkdia fb ...
Страница 530: ...530 Chapter 12 HP 8924C Replaceable Parts Replaceable Parts Listing N mkt MANUALS HP8924C ALR 24c_rpl fb ...
Страница 538: ...538 Chapter 13 HP 8924E Replaceable Parts Replaceable Parts Listing N mkt MANUALS HP8924C ALR 24e_rpl fb ...
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Страница 640: ...Index 640 N mkt MANUALS HP8924C ALR 8924CE IX V VOLUME control 61 W Write Protect Cal Data 143 ...