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71. 发明专利

JPH0712860A FREQUENCY DETECTOR 失效
公开(公告)号：JPH0712860A
公开(公告)日：1995-01-17
申请号：JP15538093
申请日：1993-06-25
申请人： TOSHIBA CORP
发明人： IGAWA HIROSHI
IPC分类号： G01R23/02 , H02J3/00
摘要： PURPOSE:To provide an inexpensive frequency detector having simple constitution. CONSTITUTION:A frequency sampling means 301 samples the AC input at a predetermined sampling frequency and delivers sampled values to a polarity change detecting means 302 and a frequency operating means 303. When sampled values x1, x2 have negative and positive polarities, respectively, the means 302 delivers a polarity change detection signal to the means 303. The polarity change detection signal is also delivered from the means 302 to the means 303 when the subsequent sampled values xn, xn+1 have positive and negative polarities, respectively. The means 303 reads in the sampled values x1, x2, xn based on the detection signal received from the means 302 and operates the fluctuation (f) of rated frequency f0 according to a predetermined formula.

72. 发明专利

JPH075212A FREQUENCY DETECTOR 失效
公开(公告)号：JPH075212A
公开(公告)日：1995-01-10
申请号：JP14323493
申请日：1993-06-15
申请人： HITACHI LTD
发明人： MANJO MINORU
IPC分类号： G01R23/02
摘要： PURPOSE:To detect the frequency of an AC power system without delay in phase free from effect of a waveform distortion during a disturbance of a three- phase AC power system and a twisting of a turbine shaft. CONSTITUTION:This apparatus has a delay means 1 which performs a digital processing of a quantity of AC electricity of a three-phase power system at a fixed cycle to delay a sampled value by one sampling time, a difference signal calculation means 2 to calculate a difference between the sampled value and an output of the delay means 1, means 3 and 4 to determine an inner product of the outputs and a frequency detection means 6 which calculates an interior angle between a sampled value of a triangle formed by the outputs of the means involved and an output value of the delay means to detect the frequency. This enables the detection of the frequency by two sampled values at a high speed thereby eliminating the effect of distortion of a waveform with the detection of no zero cross.

73. 实用新型

JPH0684374U 失效
公开(公告)号：JPH0684374U
公开(公告)日：1994-12-02
申请号：JP2634093
申请日：1993-05-20
IPC分类号： G01R23/02

74. 发明专利

JPH0695118B2 失效
公开(公告)号：JPH0695118B2
公开(公告)日：1994-11-24
申请号：JP11834986
申请日：1986-05-22
IPC分类号： G01R23/02 , G01R23/10

75. 发明专利

JPH06300793A FUNDAMENTAL FREQUENCY DETECTING METHOD FOR AC SIGNAL 失效
公开(公告)号：JPH06300793A
公开(公告)日：1994-10-28
申请号：JP8748193
申请日：1993-04-14
申请人： PIONEER ELECTRONIC CORP
发明人： SHINOHARA SATOSHI , IWAMOTO NORIKO
IPC分类号： G01R23/02 , G01R23/165
摘要： PURPOSE:To detect a fundamental frequency by a relatively simple circuit in a short time by selecting one by one from a low frequency side of divided bands of each hierarchy as a passband of an input AC signal, comparing a level of a passed signal with a reference level, and deciding whether the fundamental frequency exists in the passband or not. CONSTITUTION:An AC signal to be input is ADD-converted by an A/D converter 1, and supplied to a variable characteristic IIR filter 2. The filter 2 exhibits band pass characteristics to be decided with BPF coefficient data to be input. A signal passed through the filter 2 is supplied to one input terminal of a level comparator 5 through a detector 3 and an LPF 4. The comparator 5 compares data from a criterion level data generator 6 with input signal data, and supplies a logic '1' signal if the voltage level exceeds the criterion level. Further, a CPU 7 supplies the BPF coefficient data for deciding its passband characteristics to the filter 2, and simultaneously sends a criterion level set command to the generator 6.

76. 发明专利

JPH06207956A WIDEBAND FREQUENCY DISCRIMINATOR 失效
公开(公告)号：JPH06207956A
公开(公告)日：1994-07-26
申请号：JP319793
申请日：1993-01-12
申请人： JAPAN RADIO CO LTD
发明人： MATSUMOTO SHIGERU , OKUDE MITSUO
IPC分类号： G01R23/02 , G01R23/12 , H03D3/06
摘要： PURPOSE:To linearize output voltage of frequency signal and to obtain the frequency of transmission wave or a receiving wave easily through a simple structure. CONSTITUTION:The frequency discriminator for discriminating the frequency using power distributors 1a, 1b of distribution ratio Ko and two transmission lines 3, 4 comprises logarithmic detection amplifiers 6a, 6b comprising a power synthesizer 5 having synthesizing ratio of K1, a detector 9 having wideband characteristics, and a logarithmic amplifier 11, a subtractor 7 for subtracting signals detected and amplified through the logarithmic detection amplifiers, and a converter 8 for subjecting the subtraction result signal to reverse logarithmic conversion.

77. 发明专利

JPH06201742A CORRECTION METHOD FOR FREQUENCY DISCRIMINATION CIRCUIT OF RECEIVING SIGNAL 失效
公开(公告)号：JPH06201742A
公开(公告)日：1994-07-22
申请号：JP38393
申请日：1993-01-06
申请人： FUJITSU LTD
发明人： MURAKAMI HIRONORI
IPC分类号： G01R23/02 , H03L7/02 , H04B1/06 , H04B17/00 , H04B17/29
摘要： PURPOSE:To provide a correction method for a frequency discrimination circuit capable of correcting with high accuracy and high precision an output F/V characteristic of a discrimination circuit of all frequencies of a band by means of one test signal in the center of a specified receiving band. CONSTITUTION:Receiving input is switched by a switching unit 20, and one test signal from a test signal generator 1 for generating a signal of a center frequency fo in a specified receiving band outside is inputted and output is divided into two signals having a pi/2 phase difference to each other. Output S1 of a variable phase shifter 5 which imparts variable and plural delay time to an input signal of one of the divided output to change a phase of the output signal by plural different quantities, and an input signal S2 of the other divided output are inputted to a phase detecter 60 to be detected. By means of detection output V in accordance with a phase difference 6 between the two input S1, S2, a frequency of the receiving input is discriminated.

78. 发明专利

JPH0682500A FREQUENCY MEASURING DEVICE 失效
公开(公告)号：JPH0682500A
公开(公告)日：1994-03-22
申请号：JP25764192
申请日：1992-09-02
申请人： MITSUBISHI ELECTRIC CORP
发明人： HAMADA YOSHIO
IPC分类号： G01R23/02 , G01R23/175
摘要： PURPOSE:To allow a frequency measuring device having an I/Q phase discriminating circuit to accurately measure frequencies using a simple constitution, even if a measuring band broadens. CONSTITUTION:Frequency accuracy is determined in accordance with the polarity of an output video signal of an I/Q phase discriminating circuit 5 and discrimination among I/Q video signals repeatedly generated when a measuring band broadens is performed by switching between delay lines 10, 11 and between band pass filters 12, 13, the lines and the filters being provided on the input side of the I/Q phase discriminating circuit 5. Therefore, frequencies can be measured with accuracy even if the measuring band broadens.

79. 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.

80. 发明专利

JPH05232244A SENSITIVITY ADJUSTING METHOD FOR BODY DETECTING APPARATUS 失效
公开(公告)号：JPH05232244A
公开(公告)日：1993-09-07
申请号：JP18536892
申请日：1992-07-13
申请人： MINNESOTA MINING & MFG
发明人： IAARU BAANAADO HOOKUMAN , MAACHIN SHII HENDAASON
IPC分类号： G01N27/72 , G01R23/02 , G01V3/10 , G08G1/015 , G08G1/042
摘要： PURPOSE: To set the accurate sensitivity by synchronously deciding the length of a measuring synchronization, comparing it with a reference value, and outputting a signal indicating the presence of a vehicle when the difference of the both is larger than a threshold value. CONSTITUTION: The 'frame section' of a 'measuring frame' having larger measuring period is constituted. Each time the frame section is completed, the final count from a synchronous counter 38 is combined with the number induced from the final count generated during previous frame section to form one measured value. Then, it is compared with a reference value, and if it largely exceeds the reference value, the presence of one vehicle is indicated. A processor 20 gives a suitable output signal to a suitable primary and auxiliary output circuits. Thus, accurate sensitivity can be set.

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