Analyzing and improvement of the thermopile output signal noise ratio of a calorimeter

At present, thermoelectric technique is a popular method to setup national RF power standards. From the measurement, the Lab's temperature stability has strong affected the thermopile's output voltage. In this paper, the reason of the influence to calorimeter's measurement from Lab's temperature change is analyzed. We use the Average Temperature Block (ATB) to eliminate the affection. The measurement results of before and after ATB used is presented.