| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To securely decide a level change by arranging a detection level when there is no touch to a constant level. <P>SOLUTION: A DA converter 24 converts a digital signal of a plurality of bits output from a CPU 21 into an analog value and then supplies it to a control terminal of a gain control amplifier 17. Also, the CPU 21 generates and forwards a control signal to analog multiplexers 14, 16, a sample hold circuit 19 and an AD converter circuit 20, respectively. Further, a ROM 22 of the above unit contains a reference table 22a, for example, storing 1,600 numerical values each of which is expressed as 8-bit data. The CPU 21 enables the analog multiplexers 14, 16 to select any combination of numbers (x, y), reads a value stored in a location corresponding to the number (x, y) from among the above 1,600 values and outputs the above read value to the DA converter circuit 24 to control the gain of the gain control amplifier 17. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
