| 摘要 |
PROBLEM TO BE SOLVED: To automatically compensate temperature so that signals may not affected by loss due to a temperature-sensitive element and an internal capacitance. SOLUTION: A variable attenuator 14 outputs output signals obtained by adjusting the level of input signals according to the value of control signals. A CPU 26 including an A/D converter for receiving the input signals of the variable attenuator 14 and converting them to digital signals outputs digital signals for variable attenuator adjustment. A D/A converter 28 converts the digital signals to analog signals and supplies them to the variable attenuator 14. A reference voltage generation part 30 generates a reference voltage for converting the digital signals from the CPU 26 to the analog signals and the reference voltage is changed according to temperature change. COPYRIGHT: (C)2009,JPO&INPIT
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