| US 7,528,708 B2 | ||
| Variation detection device, data communication apparatus, and method of detecting variation | ||
| Akira Saitou, Yamagata (Japan); Yoichi Takahashi, Yamagata (Japan); Tomotake Ooba, Yamagata (Japan); Keiichi Iwazumi, Yamagata (Japan); Fujio Higuchi, Yamagata (Japan); and Keiko Kobayashi, Yamagata (Japan) | ||
| Assigned to NEC Electronics Corporation, Kawasaki (Japan) | ||
| Filed on Oct. 13, 2005, as Appl. No. 11/257,651. | ||
| Claims priority of application No. 2004-299002 (JP), filed on Oct. 13, 2004. | ||
| Prior Publication US 2006/0077048 A1, Apr. 13, 2006 | ||
| Int. Cl. B60Q 1/00 (2006.01) | ||
| U.S. Cl. 340—449 [307/10.1; 340/426.33; 340/438] | 20 Claims |
| 1. A variation detection device comprising:
a processor;
an AD converter converting a signal voltage output from a sensor to generate an AD converted value and outputting said AD
converted value to said processor;
a temperature sensor detecting a temperature of said sensor; and
a memory storing a table which indicates a relationship between temperatures and initial values,
wherein when receiving said AD converted value, said processor identifies a temperature of said sensor based on an output
of said temperature sensor, reads out an initial value corresponding to said identified temperature from said table stored
in said memory, and calculates a variation between said initial value and said AD converted value, and
wherein said variation is calculated by subtracting the AD converted value from an initial AD converted value that was measured
at a temperature at which the present AD converted value is measured.
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