An accurate RMS/DC voltage comparator

The authors describe a new instrument which is designed to operate as a null meter with a range of +or-1000 p.p.m. of typical test voltages used in high-accuracy AC calibrations. It is based on a commercially available dual-heater-type converter in a standard integrated circuit package. The accuracy of the instrument is better than 100 p.p.m. for frequencies of 50 Hz to 200 kHz. It can, however, be used for frequencies up to 1 MHz at reduced accuracy.<
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