“g”-Compensated, Miniature, High Performance Quartz Crystal...
Transcript of “g”-Compensated, Miniature, High Performance Quartz Crystal...
Hugo [email protected] 2006
Frequency Electronics Inc.
““gg””-- Compensated, Miniature, Compensated, Miniature, High Performance Quartz High Performance Quartz
Crystal OscillatorsCrystal Oscillators
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Discussion OutlineDiscussion Outline
• Introduction• Specific Applications• Osc. PN Performance under Vibration• “g”- Compensation Scheme• Compensation Test Results• The Hardware• Oscillator Spec Goals
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IntroductionIntroduction
The Issue
• Sophisticated military electronic systems aboard helicopters, missiles,and UAVs must provide superior performance while subjected tosevere environmental conditions.
• Of these dynamic disturbances, vibration, acceleration, and shock
have the greatest influence on performance.
• The Precision Quartz Oscillator is the common component in all thesesystems and is also the most sensitive to environmental disturbances.
• A chasm therefore exists between how well these systems work in the
quiescent state vs. being dynamic, due to the Qz Osc performance.
• Through electronic “g”-compensation of the Qz Oscillator, near quiescent levels performance is regained, while the platform is in the operational dynamic state.
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IntroductionIntroduction
SLCET-TR-88-1 (Rev.8.4.3) AD-A328861 (revised)
For Frequency Control and Timing ApplicationsA Tutorial
John R. VigU.S. Army Communications-Electronics Command
Attn: AMSEL-RD-C2-PTFort Monmouth, NJ 07703, USA
J.Vig@ IEEE.org
January 2001
Approved for public release.Distribution is unlimited.
QUARTZ CRYSTALRESONATORS AND OSCILLATORS
4-76
To “see” 4 km/h targets, low phase noise 70 Hz from thecarrier is required. Shown is the probability of detection of 4 km/h targets vs. the phase noise 70 Hz from the carrier of a 10 MHz reference oscillator. (After multiplication to 10 GHz the phase noise will be at least 60 dB higher.) The phase noise due to platform vibration, e.g., on an aircraft, reduces the probability of detection of slow-moving targets to zero.
100
80
60
40
20
-140 -135 -130 -125 -120 -115 -110
High NoiseLow Noise
Phase Noise (dBc/Hz)at 70 Hz from carrier, for 4 km/h targets
Prob
abili
ty o
f Det
ectio
n (%
)
Coherent Radar Probability of Detection
Original Publication:
1962,
2nd Ed. 1980
3rd Ed. 2001
John VigJohn Vig’’s reference to this book by s reference to this book by Merrill I. SkolnicMerrill I. Skolnic, recently revised, , recently revised, was very helpful in establishing the was very helpful in establishing the requirements from which oscillator requirements from which oscillator Phase Noise specs can be Phase Noise specs can be determineddetermined
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Specific ApplicationsSpecific Applications
• Radars and sensors mounted on helicopters Severe low and medium frequency vibration environment; noise translates to lower precision imaging and false target detection.
• Sensors mounted on unmanned air vehicles (UAVs)
Vibration levels during target “loitering”; noise affect sensor precision and communications data rate with the control center.
• Airborne emitter detection and signal analysis systems
Loss of detection range (vehicle must be closer to the threat for ID) and slower signal analysis process (time needed for positive ID of threat).
• Dynamic host Navigation, guidance, and targeting systems
Accuracy degradation of GPS-aided navigation, guidance, and targeting systems operating in severe environments.
• Broadband, High Data Rate Communications Systems Platform dynamics degrade the signal to noise ratio, increasing BER (bit error rate), requiring data rate decrease to maintain desired BER.
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Steady State ApplicationSteady State Application
• Using John Vig’s example of a 4 km/h moving object, being engaged by a 10 GHz X-Band Radar
Doppler Shift for Objects Moving Toward Fixed Radar (Hz)
5
0
10
15
20
25
30
40
10 100 1K 10K 100K 1M
R a
d a
r F
r e
q u
e n
c y
( G
H z
)
4 km
/h -
Man
or S
low
Mov
ing
Vehi
cle
100
km/h
- Veh
icle
, Gro
und
or A
ir
700
km/h
- Sub
soni
c Ai
rcra
ft2,
400
km/h
- Mac
h 2
Airc
raft
X-Band RADAR
~70 Hz
Courtesy of Dr. John Vig
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P h
a s
e N
o I
s e
( d
B c
/ H
z )
Single Sideband Frequency Offset from Carrier (Hz)10 100 1,000 10,000 100K 1M 10M
-160
-140
-130
-120
-110
-100
-90
-80
-70
-65
~70 Hz
10 GHz Radar Frequency Source ~performance to detect
4 km/hr. Objects
-150
““Good” 10 MHz Quartz Oscillatorphase noise performance (at rest)
“Good”” 10 GHz Quartz/DRO- combination Oscillator phase noise performance
(at rest)
10 MHz Quartz Oscillator Spec to “see”a 4 km/hr object (2 approx. - 130 dBc at ~70 Hz
σ)
Oscillator Phase Noise Performance Oscillator Phase Noise Performance for 4 km/hr. Object Detectionfor 4 km/hr. Object Detection
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Radar Radar -- Probability of DetectionProbability of Detection
Phase Noise (dBc/Hz) - 10 MHz Quartz Oscillator
P r
o b
a b
I l i
t y o
f D
e t
e c
t I o
n (
% )
100
80
60
40
20
-140 -135 -130 -125 -120 -115 -110
Higher NoiseLower Noise
at 70 Hz from the Radar Carrier Frequency, for 4 km/hr objects1σ (~68%)
2σ (~95%)
Courtesy of Dr. John Vig, (modified by HF)
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V i
b r a
t i o
n g
2 / H
z
300
0.2
0.3
0.4
0.5
10 100 1000
Frequency (Hz)
20 30 40 50 70
Helicopter
0
0.1
200
Loiter Aircraft
0.08g2/Hz0.04g2/Hz
5g2/Hz
Typical Helicopter and Loiter Typical Helicopter and Loiter Aircraft Random VibrationAircraft Random Vibration
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Frequency Offset from Carrier (Hz)
P h
a s
e
N o
i s
e (
d B
c /
H z
)
-170
-160
-150
-140
-130
-120
-110
-100
-90
-80
-70
1 10 100 1,000 10,000
Crystal Gamma of 1E-09/gCrystal Gamma of 1E-10/g
Crystal Gamma of 2E-11/gCrystal Gamma of 2E-12/g
Oscillator under Loiter Aircraft Vibration Level
(~0.04 g2/Hz)
4 km/hr Radar Detection Requirement
70 Hz
Phase Noise vs. 10 MHz Oscillator Phase Noise vs. 10 MHz Oscillator ““gg”” Sensitivity (Gamma)Sensitivity (Gamma)(Loiter Aircraft Random Vibration Environment) (Loiter Aircraft Random Vibration Environment)
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P h
a s
e N
o i
s e
(d B
c /
H z
)
Frequency Offset from Carrier (Hz)
-150
-140
-130
-120
-110
-100
-90
-80
10 100 1,000 10,000
Gamma of 1E-9/g
Helicopter 4 km/hr
detection spec
70 Hz 200 Hz
Proposed 10 MHz Oscillator Phase Noise Spec for
Helicopter Radar at rest
Gamma of 5E-11/g
Electronic Compensation
Required Shock Mount Required
Phase Noise vs. 10 MHz Oscillator Phase Noise vs. 10 MHz Oscillator ““gg”” Sensitivity (Gamma)Sensitivity (Gamma)(Helicopter Random Vibration Environment) (Helicopter Random Vibration Environment)
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Expected PN of 10 MHz Osc. “g” Sensitivity of ~5E-12/g (Helicopter Random Vibration Environment)
P h
a s
e N
o i
s e
(d B
c /
H z
)
Frequency Offset from Carrier (Hz)
-150
-140
-130
-120
-110
-100
10 100 1,000 10,000
Gamma of 5E-11/g
Helicopter 4 km/hr detection spec
70 Hz 200 Hz
Electronic Compensation
Expected performance with compensation to
~5E-12/g Shock Mount Resonance
Shock Mount
Proposed 10 MHz Oscillator Phase Noise Spec for
Helicopter Radar at rest
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Quartz Resonator responds
(E)
(B)
Z
X
Y Quartz Crystal Resonator base
Г = (x2 + y2 + z2)½Quartz Disk
The actual product
encloses the disk with a cap
Sensing devices mounted in each axis
Sensing devices respond (D)
Vibration applied to the Oscillator (C)
(A)
Electronics adjusts amplitude and phase as needed to compensate
(F)Oscillator
Output
(G)
Functional Description of the gFunctional Description of the g--Compensation Compensation Technology for Phase NoiseTechnology for Phase Noise
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The HardwareThe Hardware
Stand-alone “g”-Compensated Qz Oscillators
Master Clocks – GPS, Rb, and Compensated Qz(Maintains lock with ~ 22 gRMS, 10 to 2,000 Hz environment)
GPS Rbg-Comp Qz
Time/Frequency Sync Hold-over• Good performance
under vibration• Low PN
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Uncompensated
Compensated4 km/hr detection spec4 km/hr detection spec70 Hz70 Hz
Vibration Profile: 4g RMS total, Random; 0.08gVibration Profile: 4g RMS total, Random; 0.08g22/Hz, 10 to 200 Hz/Hz, 10 to 200 HzApproximate Sensitivity per g (Approximate Sensitivity per g (ΓΓ))10 Hz10 Hz 50 Hz50 Hz 100 Hz100 Hz
UncompensatedUncompensated 1.1 E1.1 E--99 7.9 E7.9 E--10 8.9 E10 8.9 E--10 10 CompensatedCompensated 6.3 E6.3 E--1212 2.2 E2.2 E--11 4.0 E11 4.0 E--1111
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Vibration Profile: 4g RMS total, Random; 0.08g2/Hz, 10 to 200Vibration Profile: 4g RMS total, Random; 0.08g2/Hz, 10 to 200 HzHzApproximate Sensitivity per g (Approximate Sensitivity per g (ΓΓ))10 Hz 50 Hz 100 Hz10 Hz 50 Hz 100 Hz
Uncompensated 2.2 EUncompensated 2.2 E--11 11 2.8 E2.8 E--11 2.2 E11 2.2 E--1111CompensatedCompensated 2.8 E2.8 E--12 2.5 E12 2.5 E--12 5.0 E12 5.0 E--1212
Uncompensated
Compensated4 km/hr detection spec4 km/hr detection spec70 Hz70 Hz
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Uncompensated
Compensated
4 km/hr detection spec4 km/hr detection spec70 Hz70 Hz
Vibration Profile: 4g RMS total, Random; 0.08g2/Hz, 10 to 200Vibration Profile: 4g RMS total, Random; 0.08g2/Hz, 10 to 200 HzHzApproximate Sensitivity per g (Approximate Sensitivity per g (ΓΓ))10 Hz10 Hz 50 Hz 100 Hz 50 Hz 100 Hz
UncompensatedUncompensated 7.0 E7.0 E--1111 8.9 E8.9 E--11 7.0 E11 7.0 E--1111CompensatedCompensated 1.8 E1.8 E--11 3.1E11 3.1E--11 3.5 E11 3.5 E--1111
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“g”-Sensitivity:Compensation to better than 2E-12/g, 10 Hz to 2 KHz In Production: Compensation to 1E-11
Uncompensated at Qz level, 2E-10 (best in class)
Power Consumption:100 mWIn Production: 1.5 W
Volume: 8 cm3; a reduction from traditional units, usually at least 40 cm3 or more
Short Term Stability:1E-13 @ 1 to 100 seconds In Production: 1E-12
Aging:1E-8 over 10 yearsIn Production: 1E-10 per day
Temperature Coefficient:+/- 2E-11 from -40C to +85CIn Production: +/- 1E-10
Oscillator Spec Oscillator Spec GoalsGoals