发明名称 |
Filter automatic adjustment apparatus, filter automatic adjustment method, and mobile telephone system |
摘要 |
The invention provides a filter automatic adjustment apparatus and method, and a mobile telephone system, which realizes low power consumption while adjusting a characteristic frequency of a main filter having an adjustment function to a target frequency. The filter automatic adjustment apparatus includes: a phase difference detector 104 which outputs a signal having a duty ratio corresponding to a phase difference between an input signal and an output signal of a reference filter 103 ; a comparator 105 which converts the output signal of the phase difference detector into a rectangular wave; a counter 106 which consecutively counts a predetermined interval of the rectangular wave plural times; and a determination circuit 107 which selects a count value satisfying a predetermined criterion from the plural time count values, and the filter automatic adjustment apparatus adjusts the characteristic frequency of the main filter based on the selected count value. |
申请公布号 |
US7408417(B2) |
申请公布日期 |
2008.08.05 |
申请号 |
US20060391195 |
申请日期 |
2006.03.29 |
申请人 |
MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. |
发明人 |
FUKUSEN MASARU |
分类号 |
H03L7/00 |
主分类号 |
H03L7/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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