Oscillator circuit for generating a signal whose frequency is representative of the phase shift of a four terminal network

US4078201A · kind A · utility

Assignee

• BBC Brown, Boveri & Company Ltd. · CH

Inventor

• Werner Buser · Basel, CH

Key dates

• Filing date: Jun 16, 1976
• Grant date: Mar 7, 1978
• Expiry date: Jun 16, 1996

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R25/04
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention concerns a measuring instrument for measuring phase shifts in four terminal electrical networks, where the network whose phase shift is to be measured is connected into the feedback circuit of an R-C phase shifter oscillator, and where the generated frequency depends on the phase shift of the four terminal network and of the RC-phase shifter, and where the circuit is so dimensioned that the following oscillation conditions are satisfied: EQU .phi.(.omega.) + .phi. = 0 (or integral multiples of 2 .pi.)(1) EQU .vertline.F (.omega.).vertline..multidot..vertline.H.vertline..multidot.A = 1 (2) where .phi. = phase shift of the network whose phase shift is to be measured PA1 .phi.(.omega.) = phase shift of the R-C phase shifter PA1 F (.omega.) = damping of R-C phase shifter PA1 H = damping of network whose phase shift is to be measured PA1 A = real amplification factor And where furthermore H(p) and F(p) respectively represent the transmission function of the unknown network and of the R-C phase shifter and where A is so set by regulation that equation (2) is satisfied, and finally the network H(p) arranged in the feedback circuit is a coil assembly or a transformer.