| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a detection apparatus, etc. capable of reducing adverse effects due to environmental changes such as temperature changes. <P>SOLUTION: The detection apparatus includes a drive circuit and a detection circuit. The detection circuit includes an amplifier for amplifying output signals from an oscillator; an offset adjusting circuit for adjustments for removing an initial offset voltage of output signals of the detection apparatus; a synchronous detection circuit for synchronous detection on the basis of reference signals; and a filter part for filter-processing signals after synchronous detection. The filter part includes both a discrete-time filter and a continuous-time filter provided for the preceding-stage side of the discrete-time filter. The continuous-time filter has such frequency characteristics as to remove offset variations of undesired signals due to environmental changes. The continuous-time filter attenuates the offset variations of undesired signals which appear in a frequency band of frequencies k×fd due to synchronous detection to the amplitude of desired signals or less. <P>COPYRIGHT: (C)2008,JPO&INPIT |
