Table of contents

VHF Crystal Oscillators

Why do we need better local oscillators?

Frequency Stability

How stable do our microwave LOs need to be?

Slide 5

Slide 6

What about long-term stability?

Can we do it?

Slide 9

Highest performance Local Oscillator System

Adequate local oscillator system

What performance can be expected from a crystal resonator?

Slide 13

So what? We can solve those problems with a cheap crystal heater, can’t we?

Aging

What is a crystal?

Vibration Mode

What determines the resonant frequency of a crystal resonator?

Crystal Aging

Selecting Crystals - Part 1

Temperature/frequency characteristic of AT-cut crystal

What determines the temperature/frequency characteristics of a crystal?

Cutting a quartz blank

Simplified equivalent Circuit of Crystal Resonator

Vibration modes in AT-cut crystal

A More Realistic Equivalent Circuit!

Simplified Equivalent circuit of 96MHz 5th overtone Crystal Resonator at resonance

Slide 28

Slide 29

Reflection and transmission oscillator models

Slide 31

A Generic Transmission-Mode Oscillator

Oscillator Linear Analysis

Slide 34

Oscillator Linear Analysis

Slide 36

Oscillator noise

Slide 38

Slide 39

Single-sideband noise

Oscillator Noise

Slide 42

Resonator term of Leeson Equation

Amplifier term of Leeson Equation

Flicker Noise term of Leeson Equation

PowerPoint Presentation

Slide 47

Limitations of Leeson Equation

Optimising the Resonator

Slide 50

Slide 51

Slide 52

Slide 53

Optimising the Amplifier/Limiter

Optimising the Amplifier

Slide 56

Slide 57

Slide 58

Slide 59

Slide 60

Slide 61

Slide 62

Slide 63

Slide 64

Slide 65

Optimising the Limiter

Slide 67

Slide 68

Slide 69

Slide 70

Putting it all together

Slide 72

Slide 73

Slide 74

Slide 75

Slide 76

Getting the power out

Slide 78

Slide 79

A 94MHz Driscoll oscillator

Slide 81

Pulling the oscillator frequency

Measuring phase noise

Frequency multipliers

Slide 85

Slide 86

Slide 87

Slide 88

Slide 89

References

Contact Information

E-mail: gw4dgu@blaenffos.org

Homepage: www.blaenffos.org

Further information:
This is a slightly expanded version of the presentation on VHF crystal oscillator design given at the Martlesham Microwave Roundtable, 10 November 2002

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