| 摘要 |
PURPOSE:To measure a wide range of temperature at a high accuracy, by providing a frequency measuring circuit for measuring oscillation frequency of a thermosensitive oscillation circuit to stratify the frequency-temperature characteristics in terms of frequency. CONSTITUTION:This apparatus comprises a thermosensitive oscillation circuit 12, equipped with a thermistor, in which the frequency varies exponentially according to changes in the temperature and a frequency measuring circuit 13 for measuring the oscillation frequency and a frequency data (f) from the circuit 13 is converted to a temperature data T with a temperature conversion circuit 9 to be displayed 10. Here, the frequency-temperature characteristic is divided in terms of a fixed frequency range and a linear approximation is applied to each range. Approximated straight lines are expressed by the respective inclinations and intersections with the temperature axis and the inclinations and the intersections present sensitivity values and offset values to be memorized into a sensitivity memory circuit 9a and an offset memory circuit 9c respectively. With such an arrangement, correspondingly to the data (f) inputted, the circuits 9a and 9c output a sensitivity value (a) and an offset value (c). A temperature data computing circuit 9d receives the input of the data (f) and the corresponding values (a) and (c) to obtain a data T on the approximate straight lines. |
