Isotech microKcallabmagazine free download

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THE INTERNATIONAL JOURNAL OF METROLOGY Innovative ADC Sets New Temperature Calibration Standards Implementation of a Commercial 2006 Quantum Hall Resistance System OCTOBER NOVEMBER GPS Receiver Calibration DECEMBER Going Paperless and Wireless Better Accuracy in Temperature Calibration and Measurement through a New Type of Analog-to-Digital Converter Paul Bramley Metrosol Limited, UK John Pickering Metron Designs Limited, UK This article describes a new reversal-switched DC precision thermometer that achieves performance levels previously attained only with AC resistance bridges. The microK is designed for use in secondary temperature calibration and high accuracy temperature measurement applications (to 0.4mK uncertainty) and is the only precision thermometer that can work with both resistance thermometers and thermocouples at sub mK uncertainties. The use of a touch-screen instrument of its type, thereby providing the highest possible reliability. The core technology is a wholly new type of ADC converter) in the feedback loop is replaced by a 5-bit PWM (pulse-width modulation) DAC. The effect of this is to reduce then determined by the electronic devices used in the ADC and measurement system, which are lower than existing comparable instruments. Introduction EMF generated by a thermocouple is measured in order Although we rightly focus on the thermodynamic to determine its temperature. Again, the demands on challenges when making high accuracy temperature the electrical measurement rival those of the electrical measurements, the electrical measurement requirements for calibration laboratory; a gold-platinum thermocouple has achieving low measurement uncertainty are comparable to those of a good electrical laboratory. The main temperature sensors used are PRTs (platinum resistance thermometers). The SPRTs (standards PRTs) used in high accuracy full range of the thermocouple). This again represents a calibration work comprise thin and lightly suspended coils demanding electrical measurement objective. of platinum wire, the resistance of which is measured to determine their temperature. The Need for a New ADC for a 25 The ADC in a precision instrument is the "measurement engine." Its performance is the starting poin