Constructing Prototype Lock-in Amplifier with LabVIEW & DAQ
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Constructing Prototype Lock-in Amplifier with LabVIEW & DAQ Xiaoyu Wu 08300290011 Dept. of Physics, Fudan University
description
Constructing Prototype Lock-in Amplifier with LabVIEW & DAQ. Xiaoyu Wu 08300290011 Dept. of Physics, Fudan University. What is Lock-in Amplifier(LIA)?. Detect & Measure Signals Even with overwhelming noise Typical S/N ratio -60dB. Signal + Noise. Amplitude + Phase as DC. - PowerPoint PPT Presentation
Transcript of Constructing Prototype Lock-in Amplifier with LabVIEW & DAQ
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Constructing Prototype Lock-in Amplifier with LabVIEW & DAQ
Xiaoyu Wu08300290011
Dept. of Physics, Fudan University
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What is Lock-in Amplifier(LIA)?
• Detect & Measure Signals• Even with overwhelming noise• Typical S/N ratio -60dB
Signal + Noise
Amplitude + Phase as DC
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Typical Application: Scanning Tunneling Spectroscopy
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Principle of LIA
• Phase Sensitive Detection• Orthogonality of Sinusoidal Functions
LOW-PASS FILTER
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LabVIEW & DAQ
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Realizing the Algorithm
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Demonstration
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Features
• Signal Frequency: ~Hz to ~kHz• Signal Amplitude: 0.005V tested• Sampling Rate: maximum 50kHz, 40kHz tested
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Drawbacks
• S/N Ratio• Function Generator