Landis & Gyr Technology Innovation Ag

Jan Petr

Jacob De Vries

Erich Jeker

Raul Cermeno

Peter Hodel

A system for measuring the energy output from one or more electrical energy sources first makes an analog power measurement, and converts the resultant output into digital form. The A/D converter includes a sigma-delta modulator in series with a digital filter. Then, the output from the A/D converter is inputted to a digital quantizer via a serial interface. A programmable calibration value is also inputted into the digital quantizer from a computer via a non-volatile memory, such that the operating level/calibration of the digital quantizer is controllable by the computer.

Analog-to-digital measurement and calibration system for electrical

A temperature compensation circuit for a power measurement device includes an input sensor, with a temperature-dependent transmission factor (K.sub.H,T), connected to a signal processor with a temperature-dependent transmission factor (K.sub.S,T). Transmission factor (K.sub.S,T) of the signal processor is inversely proportional to a temperature-dependent reference voltage (U.sub.R,N,T), which is inputted to the signal processor in order to render the combined transmission factor (K.sub.H,T .multidot.K.sub.S,T) temperature independent. To accomplish this, a temperature coefficient value of reference voltage (U.sub.R,N,T) must be equal to the sum of a temperature coefficient value of transmission factor (K.sub.H,T) and a temperature coefficient value of transmission factor (K.sub.S,T). The desired temperature coefficient value of reference voltage (U.sub.R,N,T) is predetermined, and can be programmed into the inventive temperature compensation circuit, so as to accommodate variations in temperature coefficient characteristics of the internal components.

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Oberwil/Zug, Switzerland

Jan Petr