Linearizing circuit for meter displays

Apparatus for providing a correction signal to be effective in one portion only of the range of an input signal for an electrical meter comprising

• a first circuit receiving the input signal and a reference signal and providing a first circuit output corresponding to the input signal,
• a second circuit receiving said first circuit output and an offset signal and providing a second circuit output having zero correction signal points at each end of the one range portion which are determined by said offset signal and having a maximum correction signal point between said zero correction signal points having a location in the range of the input signal which is determined by said reference signal,
• means for inverting said second circuit output
• and means for combining said second circuit and inverted second circuit outputs and for summing a selected part of said combined outputs with the meter input signal.

A method of compensating for error in one part of the range of an electrical meter adapted to operate in response to an input signal within the range between zero and a maximum input signal value, wherein compensation within the one part of the range is substantially ineffective in the remaining parts of the range, comprising the steps of

• combining the input signal with a reference signal and converting the combined signal to a signal corresponding to the input signal and having a zero reference corresponding to the mid point of the one part of the range,
• forming a signal envelope defining the locus of maxima for the compensation signals and defining the ends of the one part of the range at the envelope ends,
• inverting the signal envelope defining the locus of maxima,
• coupling the signals defined by the locus of maxima and the inverted signal envelope to separate points on a voltage divider,
• picking off a selected portion of the signal across the voltage divider, and
• summing the selected portion with the input signal.