[Relationship between temperature range and wavelength bandwidth for multi band pyrometry].
In the present paper, based on the linearity spectral emissivity model with two parameters in the narrow investigated waveband, we extend tri-wavelength pyrometry to tri-band pyrometry through waveband measurements of radiation temperature. In tri-band pyrometry, in order to realize the non-distortion measurement, considering the effect of the dynamic range and the minimum sensibility of the sensor on the coupling relation of multi-channel signals, the restriction condition of the effective temperature measurement range is discussed. However, under the assumption of the fixed sensor parameters, the measurement bandwidth of the sensor is an important influencing factor to the effective temperature measurement range in applications of tri-band pyrometry. Then for the measured objects with the known radiation characteristics, the variation of the effective temperature measurement range with the bandwidth of the sensor is presented through numerical simulations. So the required condition of bandwidth of the sensor is theoretically determined through the above discussions of the effective temperature measurement range. The analyses in this paper may provide the necessary theoretical guides to the design of the sensor of radiation temperature measurement.