Adaptive Noise Cancellation: A Panacea

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Adaptive Noise CancellationA Panacea

• Evans, R. Adhikari

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The Concept

• 5000 Channels
• 1 GW Channel
• Signal DARM - noise

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Wiener Filter
Norbert Wiener, MIT
Block Toeplitz
Cross Correlation Matrix
Input Signal (PEM) Covariance Matrix
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Wiener Filter Sim
H1
L1
x10
x7

• H1 L1 DARM (S5)
• All Guralp STS2
• Vault not used
• Requires 9 GB RAM
• Levinson-Durbin

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Adaptive Filtering /Neural Network
Keenan Pepper
Elena Gasparri
LMS Algorithm (1st chapter of textbooks)
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ATNF
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Filtered-X LMS
Edwards, Thesis (declassified) Naval
Research Postgraduate School
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Applications

• Seismic Noise (0 - 40 Hz)
• Upconversion
• Lock Acquisition
• Bilinear (Crab shoulder)
• Acoustic Noise (50-900 Hz)
• Magnetic (power lines)
• H1/H2 correlation
• MICH/PRC/SRC

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From LMS to Filtered-X
Noisy Signal

• LMS

FIR
Noise Witness
Cleaner Signal
Adapt
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From LMS to Filtered-X

• Injecting into a high gain servo loop

Total Control Signal
FIR
Noise Witness
G
Servo Control Signal
Adapt
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From LMS to Filtered-X

• Separated Actuators
• Special case of Filtered X-LMS

Total Control Signal
FIR
Noise Witness
A2
G
A1
Servo Control Signal
Adapt
C
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At the 40m

• Test on input mode-cleaner

MC Length
FIR
Seismic Sensors
MC1
G
MC2
MC_L
Adapt
C
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At the 40m
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At the 40m
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And more !