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An investigation into mixer in radio
communications systems
ABSTRACT
Software radio is one of the hotspots in radio communication
and military research. Due to the processing speed of A/D/A
conversion and DSP processor, software radio often adopts
inter-specific schemes based on digital conversion technology.
That is to say, by using specific DDC&DUC or running relevant
algorithm, software radio transforms the sampling rate to
enable DSP processors bring real-time signal to success. In
this dissertation, the mixer and NCO in the DDC are investigated,
some typical cases are focused on., then on the basis of result
of logic synthesis, the utilization rate of FLE10K's logic
resource is analyzed
In the first place, the dissertation presents Current situation
and the trend of the modern radio communication and discusses
the problem at present, then gives the theory of radio communication
and the function, as well as the principle of the mixer. The
dissertation emphases mainly on the design of the mixer. The
design of the mixer is discussed from two aspects: the design
of the NCO, the design of the multiplier. The design of the
NCO includes the design of four function module, that is,
Phase accumulator module; module producing the harassing code;
accumulator module and module for memory altitude of wave.
In the course of design, schematics, VHDL, LPM, MAX+ plusII
and FLEX10K are all applied, then on the basis of result of
logic synthesis, the utilization rate of FLE10K's logic resource
is analyzed. When we design the NCO, we adopt the technology
of the DDS, as a result, we can control the frequency flexibly.
Finally we give some typical cases.
Key Words: software radio; DDC; NCO; DDS; Mixer; FLE10K
ACKNOWLEDGEMENTS
Many people have been involved with the compilation of this
project. So my thanks goes out to Dave Gray my project mentor
at the University of Central England for helping and answering
all my questions. To xxxxxx my work mentor xxxxxx and to xxxxxx
at GB Spedition for the information to enable my calculations
to make sense. I also want to thank my friends for putting
up with me constantly talking about this project, their help
proof reading and their encouragement, thank you xxxxxx.
CONTENTS PAGE
ABSTRACT 1
ACKNOWLEDGEMENTS 2
CONTENTS PAGE 4
GLOSSARY 5
LIST OF DIAGRAM 6
1.0 INTRODUCTION 7
1.1 Current situation and trend of the modern radio communication
7
1.2 The questions discussed in this thesis 10
2.0 OVERVIEW 11
2.1 Basic principle of radio communication 11
2.2 The function and principle of mixer 14
2.2.1 The function of mixer 14
2.2.2 The principle of work of the mixer 14
3.0 THE THEORY OF THE ORTHORHOMBIC AND DIGITAL MIXER 16
3.1 The theory and block diagram of the orthorhombic and digital
mixer 16
3.2 Mathematical analysis 17
4.0 THE DESIGN AND REALIZATION OF HARDWARE OF THE ORTHORHOMIC
AND DIGITAL MIXER 17
4.1 The design of NCO 18
4.1.1 Phase accumulator module 18
4.1.2 Module producing the harassing code 20
4.1.3 Accumulator module 21
4.1.4 Module for storing altitude of wave 22
4.2 The realization of the NCO 23
5.0 THE DESIGN AND REALIZATION OF THE MULTIPLIER 23
5.1 The design of the multiplier with VHDL language 23
5.2 The design of the multiplier with schematic diagram 24
6.0 THE APPLICATION OF MIXER 25
6.1 Several products of mixers 25
6.2 An architecture used for transmission 28
7.0 CONCLUSION 34
REFERENCES 35
GLOSSARY
DUC Digital Up Conversion
DDC Digital Down Conversion
NCO Numerically-Controlled Oscillator
DDS Direct Digital Synthesizer
FCW Frequency Control Word
ONM Orthorhombic and Digital Mixer
LIST OF DIAGRAM
Figure 1.1 The ideal structure and feasible scheme of software
radio communication
Figure 2.1 The makeup of communication system
Figure 2.2 The composition of the mixer
Figure 3.1 Block diagram of the orthorhombic and digital mixer
Figure 4.1 The structure of DDC
Figure 4.2 The circuit of the NCO
Figure 4.3 The basic circuit of phase accumulator
Figure 4.4 The diagram of wave simulation of phase accumulator
Figure 4.5 The diagram of time simulation of phase accumulator
Figure 4.6 The circuit of module for storing sine altitude
Figure 5.1 The circuit of multiplier
Figure 6.1 Functional Block Diagram
Figure 6.2 Functional Block Diagram
Figure 6.3 Functional Block Diagram
Figure 6.4 The architecture used for transmission
Figure 6.5 A block diagram of a mixer in accordance with the
circuit
Figure 6.6 A schematic diagram of a mixer in accordance with
the circuit
Figure 6.7 A block diagram of a communication device in accordance
with the circ
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