Power metering circuit for active unit - converts voltage and current into random pulse trains, from which further pulse trains are derived, forming output for counter

摘要

Measurements are made by product formation of voltage by current, whose values are converted into random pulse trains whose mean values are proportional to voltage and current. Positive and negative signal components of voltage (U) and current (1) are converted into pulse trains (Ax, Bx, Ay, By) by means of a polarity coder (1) two comparators (4, 5) a signal converter (6) a noise voltage source (7) and a logic network (2, 3). The differences between pulse probabilities in the pulse trains allocated to voltage and current are with correct polarities proportional to voltage and current. A further logic circuit links the four pulse trains (Ax, Bx, Ay, By), so that the pulse probabilities of resulting pulse trains (Az, Bz) are proportional to the product of voltage and current. The measurement result is derived from the pulse trains by a reversible counter.