eee 432 measurement and instrumentation -...

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EEE 432

Measurement and Instrumentation

Lecture 7

Analog Signal processing

Prof. Dr. Murat Aşkarİzmir University of EconomicsDept. of Electrical and Electronics Engineering

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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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Signal processingAnalog Signal Processing

Filters

– Passive

– Active

Signal amplification

Signal attenuation

Differential amplification

Signal linearization

Bias (zero drift) removal

Signal Integration

Signal Differentiation

Voltage follower (pre-amplifier)

Voltage comparator

Voltage-to-current converter

Current to-voltage converter

Phase-sensitive detector

Lock-in amplifier

Signal addition

Signal multiplication

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Signal processingDigital 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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Signal processingFilters

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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FiltersLow Pass Filter

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FiltersHigh Pass Filter

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FiltersBand Pass Filter

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FiltersBand Reject Filter

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FiltersPassive Filters

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FiltersActive Filters

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Analog Signal ProcessingSignal Amplification

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Analog Signal ProcessingSignal Attenuation

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Analog Signal ProcessingDifferential Amplification

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Analog Signal ProcessingSignal Linearization

Light intensity transducers typically have an exponential

relationship between the output signal and the input light

intensity, i.e.: VI = Ke-aQ

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 ProcessingBias Removal

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Analog Signal ProcessingSignal Integration

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Analog Signal ProcessingSignal Differentiation

dt

dVRCV

R

V

dt

dVC

inout

outin

0

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Analog Signal ProcessingVoltage Comparator

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Analog Signal ProcessingVoltage-to-Current Converter

543

354

42531

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2

RRR

RI

VRR

R

RRRRR

VRR

RI

m

sat

ml

in

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Analog Signal ProcessingCurrent-to-Voltage Converter

IRVout

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Signal processingAnalog Signal Processing

Filters

– Passive

– Active

Signal amplification

Signal attenuation

Differential amplification

Signal linearization

Bias (zero drift) removal

Signal Integration

Signal Differentiation

Voltage follower (pre-amplifier)

Voltage comparator

Voltage-to-current converter

Current to-voltage converter

Phase-sensitive detector

Lock-in amplifier

Signal addition

Signal multiplication

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Signal processingDigital 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