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2. 发明专利

JPH0658963A METHOD AND APPARATUS FOR MEASURING FREQUENCY 失效
公开(公告)号：JPH0658963A
公开(公告)日：1994-03-04
申请号：JP21433692
申请日：1992-08-11
申请人： SONY CORP
发明人： OOISHI TAKEO
IPC分类号： G01R23/02 , H03L7/06
摘要： PURPOSE:To obtain a frequency measuring apparatus in which a PLL circuit itself can be taken into advantage by providing means for capturing an oscillator control signal in a PLL circuit, means for measuring the frequency of output signal from PLL based on the control signal, and means for estimating the frequency of input signal. CONSTITUTION:A phase comparator 1 compares the phases of input and output signals and delivers an error signal to a loop filter. The loop filter comprises a multiplier 2 and an integrator 3 and determines data for controlling a numeric control oscillator 4 based on the error signal from the comparator 1. The oscillator 4 can control the oscillation frequency based on the control data. An I/O unit 8 delivers control data from the oscillator 4 to a CPU 7. A ROM 5 stores a program and a RAM is a working memory for the CPU. An output unit 9 displays the results. The oscillator 4 oscillates at a frequency determined for the control data. This constitution determines an oscillation frequency through calculation based on a control data being input to the oscillator 4.

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