| 摘要 |
PURPOSE:To make it possible to display negative temperatures and to observe low temperatures efficiently, by obtaining the difference between a temperature signal and a temperature signal of 0 deg.C via two subtracters, and outputting the judging signal for positive or negative sign. CONSTITUTION:In the case the temperature of an image pickup body is -25.6- 150 deg.C, an infrared-ray image signal is converted into 11-bit binary digit signals B1-B11, with LSB as 0.1 deg.C. The signal B1-B8 are inputted to the subtracter 2, and the signals B9-B11 are inputted to the substracter 1. In the case of 0 deg.C, the 9th bit B9 is a 1 and other bits are a 0. The positive or negative sign of the temperature is judged by the upper 3 bits, B11-B9. The upper 3 bits for 0 deg.C are subtracted from the upper 3 bits of the input digital signal in the subtracter 1, and the judging signal Pm for the positive or negative sign is outputted. The difference between the input signal of the lower 8 bits and the signal for 0 deg.C is calculated in the subtracter 2, and the difference is inputted to a converter 7 via a selecting circuit 3. The 3-bit signal from AND circuits 4-6 are added, and the temperature is displayed 8. In this system, the negative temperature can be displayed, and the low temperatures can be observed efficiently. |
