Self tuning measuring cct for voltage and current converter testing - uses analogue-digital converters to avoid instability

摘要

The circuit has separate digital displays of the real and imaginary components of a measured variable relative to an A.C. reference voltage. The A.C. input voltage signal forming the measured variable is fed to two phase rectifiers which are synchronised by the reference voltage either in phase or 90 deg. out of phase. An analogue-digital convertor receives the output signal of one phase rectifier as a first control signal and the output signal of a reference voltage rectifier as a second control signal. A second analogue-digital convertor receives the output signal of the other phase rectifier as a first control signal and the sum of the output signals of the first phase rectifier and reference voltage rectifiers as a second control signal.