Digital Measurement Techniques

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The second edition of the highly successful text is intended for use as an introductory course or a second course in Instrumentation. The reviewers comments on the first edition helped refine and crystalise related material leading to the reorganisation of chapters and addition of: l Software-controlled measurements l Time interval measurement when the two events occur arbitrarily,and to indicate the order of occurrence, and a practical set up for the time interval measurement l Multi-phase sequence indicator l Decibel meter l Input circuitry of a frequency counter l Measurement of low-frequencies in a narrow band l Basics of ac bridges l Quality and dissipation factor measurement by phase compensation technique l Impedance measurement in the Cartesian coordinate form l Worked examples provided to illustrate the concepts l Unsolved problems to help students develop skills in using theory. Table of Contents Preface to the Second Edition Preface to the First Edition Introduction: Why Digital Measurement at All? Philosophy of Digital Measurement Software-Controlled Measurements About Other Chapters Problems Digital Time Measurement Techniques: Introduction Measurement of a Time Interval between Two Events Error in time interval measurement Vernier Technique for Small Time Interval Measurement Measurement of a time interval smaller than the clock period Resolution Precautions Measurement of time Interval with Constraint Events occur arbitrarily Saturated lapse time measurement Measurement of a Periodic Time Capacitance of a Periodic Time Phase Measurement Requirements of an ideal phase meter Phase measurement through time measurement Direct phase measurement Automatic accumulation method Phase measurement at a single low frequency Phase measurement without frequency error Micro-controller based phase measurement Multi-Phase Sequence Indicator Measurement of Time Interval between Two Events Defined by Voltage Levels Time constant measurement Accurate measurement of low time constant Measurement of Capacitance Measurement of Quality Factor of a Ringing Circuit Decibel Meter Problems Bibliography Digital Frequency Measurement Techniques: Introduction Frequency Measurement Measurement of the Ration of Two Frequencies High Frequency Measurement Frequency difference expansion method Average Frequency Difference Measurement Applications Power System Frequency Deviation Measurement Fast Low-Frequency Measurement Measurement of Low-Frequencies in a Narrow Band Up Counting Complementary counting Down Counting Time Reciprocating Circuit Frequency range and accuracy Fast Low-Frequency Measurement of Sinusoidally Varying Signals Peak Frequency Measurement A simpler scheme for the maximum minimum indicator Problems Bibliography Digitally Programmable Circuits: Introduction Digitally Programmable Resistors Digitally Programmable Dividers Minimal Digital Programmable Gain Amplifiers Remarks Programmable Schmitt Triggers Programmable Dual-Polarity Gain Amplifiers Programmable Gain Amplifier with Dual-Polarity outputs Two Stage Programming Programmable Gain Amplifiers: Applications Programmable Gain-Constant Circuits Programmable Notch Filters Programmable Biquads Problems Bibligraphy Digital-to-Analog Converters: Introduction Output-Input Relation DACs Derived from Programmable Gain Amplifiers Weighted-Resistor DACs Two-stage weighted-resistor DACs Multi-stage WR-DACs Weighted-Current DACs Weighted-Reference Voltage DACs Ladder DACs Realization of { N x L} DAC Minimum spread { N x L} ladder DAC DAC with the least number of resistors Minimum total resistance DAC realization Equal-valued resistor Minimum total resistance DAC realization Equaal-valued resistor DAC Switches A Current Driven DAC The Inverted Ladder DAC Binary-Weighted Charge DAC Input Output Formats of a DAC Hybrid Multiplier and Divider Problems Bibliography Digital Voltage Measurement Techniques: Introduction Indirect Type Analog-to-Digital Converters Voltage-to-time converters Voltage-to-frequency converters Operations in Direct Type Analog-to-Digital Converters Sampling Theorem Time Division Multiplexing Quantization Direct Type Analog-to-Digital Converters Digital ramp converter Tracking type analog-to-digital converter Successive approximation coverter Multiple threshold analog-to-digital converters Comparison Input Circuitry of a Digital Voltmeter Auto-zero circuit Bipolar operation Buffer circuit Protection Auto-ranging Sample and hold circuit Problems Bibligraphy Digital Voltage Ratiometric Measurement Techniques: Intoduction Ratiometric Measurement Technique Voltage ratio meters Applications Frequency meter for sinusoidal signals Modulation index meter Measurement of Q The tand-d meter (series RC circuit) The tand-d meter (parallel RC circuit) Measurement of a complex impedance Digital ohmmeter Digital capacitance meter Problems Bibliography Sampling Techniques: Introduction Two Basic Theorems Non-integral value theorem Zero summation theorem Sampling Distinct Sampled Instants Theorem Same Sampled-Magnitude Set Theorem Correspondence between the Samples Mean and RMS Value Theorem Power Evaluation Theorem Special case AC power measurement Energy measurement Voltage Measurement Current measurement Other measurement Problems Bibliography Index