An audio frequency multiplier with planar thermal converters for power measurements

A multiplier based on thermal converters was developed for the use in broad band power measurements. The topology of the multiplier is of simple design and suppresses its static errors by means of an improved summing circuit. It employs fast synchronous ac-dc transfer technique to shorten the measurement time. The evaluated measurement uncertainties are of the order of some 10^-6 for frequencies up to 20 kHz and some 10^-5 for frequencies up to 100 kHz.