发明授权
- 专利标题: Frequency stabilization circuit using signal level threshold
- 专利标题(中): 频率稳定电路采用信号电平门限
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申请号: US965671申请日: 1997-11-06
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公开(公告)号: US6029055A公开(公告)日: 2000-02-22
- 发明人: Hideaki Nobusawa
- 申请人: Hideaki Nobusawa
- 申请人地址: JPX Tokyo
- 专利权人: NEC Corporation
- 当前专利权人: NEC Corporation
- 当前专利权人地址: JPX Tokyo
- 优先权: JPX8-318521 19961115
- 主分类号: G01R23/15
- IPC分类号: G01R23/15 ; H03J7/06 ; H03L7/14 ; H04B1/26 ; H04B1/06
摘要:
A frequency stabilization circuit includes a local oscillator, a mixer, a level comparator, a frequency comparator, and a controller. The local oscillator outputs a local oscillation signal in accordance with a control voltage. The mixer converts a received radio frequency signal into an intermediate frequency signal using the local oscillation signal from the local oscillator. The level comparator compares a DC voltage corresponding to the intermediate frequency signal from the mixer with a reference voltage to determine whether the reception electric field level of the radio frequency signal is high or low. The frequency comparator compares the frequency of the intermediate frequency signal from the mixer with the frequency of the reference signal to output frequency difference information. The frequency comparator outputs previous frequency difference information when the comparison result of the level comparator indicates a decrease in reception electric field level. The controller outputs the control voltage to the local oscillator in accordance with the frequency difference information from the frequency comparator.
公开/授权文献
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