A frequency-independent phase shifter, that provides a precise phase shift, variable from 0 to 360ΰ, is described. With the use of. a microcontroller and feedback arrangement, the phase shift only depends on the ratio of two DC voltages. A stable, drift-free operation with good accuracy is hence obtained over the AF range. © 1995, IEE. All rights reserved.

K. Sudhakar Rao

Vignesh Jagadeesh Kumar

Panchapagesa Sankaran

Digital filters

Electric network analysis

Feedback

Phase shift

SCHEMATIC DIAGRAMS

Voltage control

FREQUENCY INDEPENDENT VARIABLE-PHASE PHASE SHIFTER

Microcontrollers

Phase shifters

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Electronics Letters

A scheme for measuring the C and tan δ (dissipation factor D) values of a capacitor is described in this paper. Comparing the unknown capacitor to a standard capacitor and employing three-phase sensitive detectors and two digital volt-meters, the parameters of the unknown capacitor are determined. The method facilitates testing of a given capacitor at a desired frequency as well as voltage. The feasibility of the scheme is established by building a prototype. The accuracy of the prototype unit for the measurement of C is ±0.2% and that for tan δ is ±2.5%.

IEEE Transactions on Instrumentation and Measurement

Measurement of C and tan δ of a capacitor employing PSDs and dual-slope DVMs

Precision frequency-independent variable-phase phase shifter

Journal	Electronics Letters
ISSN	00135194
Open Access	No