EEE 432 Measurement and Instrumentation Lecture 7 Analog Signal processing
Prof. Dr. Murat Aşkar İzmir University of Economics Dept. of Electrical and Electronics Engineering
Signal processing
. Signal processing is concerned with improving the quality of the reading or signal at the output of a measurement system, and one particular aim is to attenuate any noise in the measurement signal that has not been eliminated by careful design of the measurement system . Analog signal processing . Digital signal processing
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1 Signal processing Analog Signal Processing
. Filters . Signal Differentiation – Passive . Voltage follower (pre-amplifier) – Active . Voltage comparator . Signal amplification . Voltage-to-current converter . Signal attenuation . Current to-voltage converter . Differential amplification . Phase-sensitive detector . Signal linearization . Lock-in amplifier . Bias (zero drift) removal . Signal addition . Signal Integration . Signal multiplication
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Signal processing Digital signal processing . Sample and hold circuit . Analog-to-digital (A/D) conversion . Digital-to-analog (D/A) conversion . Digital filtering . Autocorrelation . Other digital signal processing operations
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2 Signal processing Filters
Filter : a circuit that is designed to pass signals with desired frequencies and reject or attenuate others 4 types of filters: 1. Low-pass filter: passes low frequencies and stops high frequencies 2. High-pass filter: passes high frequencies and rejects low frequencies 3. Band-pass filter: passes frequencies within a frequency band and blocks or attenuates frequencies outside the band 4. Band-reject filter: passes frequencies outside a frequency band and blocks or attenuates frequencies within the band
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Filters Low Pass Filter
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3 Filters High Pass Filter
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Filters Band Pass Filter
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4 Filters Band Reject Filter
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Filters Passive Filters
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5 Filters Active Filters
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Analog Signal Processing Signal Amplification
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6 Analog Signal Processing Signal Attenuation
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Analog Signal Processing Differential Amplification
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7 Analog Signal Processing Signal Linearization
Light intensity transducers typically have an exponential relationship between the output signal and the input light -aQ intensity, i.e.: VI = Ke where Q is the light intensity, VI is the voltage level of the output signal, and K and a are constants.
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Analog Signal Processing Bias Removal
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8 Analog Signal Processing Signal Integration
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Analog Signal Processing Signal Differentiation
dV V C in out 0 dt R dV V RC in out dt
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9 Analog Signal Processing Voltage Comparator
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Analog Signal Processing Voltage-to-Current Converter
R2 I Vin R1R3
R1R3 R5 R2 R4
Vsat R4 R5 R3 Im Rml R3 R4 R5
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10 Analog Signal Processing Current-to-Voltage Converter
Vout IR
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Signal processing Analog Signal Processing
. Filters . Signal Differentiation – Passive . Voltage follower (pre-amplifier) – Active . Voltage comparator . Signal amplification . Voltage-to-current converter . Signal attenuation . Current to-voltage converter . Differential amplification . Phase-sensitive detector . Signal linearization . Lock-in amplifier . Bias (zero drift) removal . Signal addition . Signal Integration . Signal multiplication
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11 Signal processing Digital signal processing . Sample and hold circuit . Analog-to-digital (A/D) conversion . Digital-to-analog (D/A) conversion . Digital filtering . Autocorrelation . Other digital signal processing operations
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