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31. 发明专利

JPS5460990A EXCITING METHOD OF EDDY CURRENT INSPECTION COILS 失效
公开(公告)号：JPS5460990A
公开(公告)日：1979-05-16
申请号：JP12740877
申请日：1977-10-24
申请人： NIPPON STEEL CORP
发明人： WATANABE SEIICHI , KAWAMURA KOUJI , ICHIJIMA ISAMU , MIYAGAWA KAZUO
IPC分类号： G01N27/90
摘要： PURPOSE:To eliminate the effect of switching noise and perform eddy current inspection of good accuracy by flowing an exciting current upon completion of selection and connection of an inspection coil and releasing the connection after a fixed time upon stopping of the current and selecting the next inspection coil. CONSTITUTION:A clock pulse generating circuit 1 generates pulses S1 and a count down circuit 2 counts the pulses S1 and generates a trigger signal S2. A shift register drive circuit 3, inputted with the pulses S1 and signal S2, generates the clock signal S3 and set signal S4 which have a delay than the rise of the trigger signal. Both of these signals are inputted to a swiching control circuit 6, which in turn (n) parallel outputs to an electronic switching circuit 7 at the timing of the signal S3. The circuit 7 consists of (n) pairs of electronic switch groups and the switches of the respective pairs conduct only for the output period of the control circuit 6, putting the respective pairs conduct only for the output period of the control circuit 6, putting he respective pairs of inspection coils of (n) pairs of the inspection coils 8 connecting to the circuit 7 in an operating state. Thereby, the effect of noise by switching may be eliminated.

32. 发明专利

JPS5460544A CORRECTING METHOD FOR ELECTRIC SIGNAL DISTORTION 失效
公开(公告)号：JPS5460544A
公开(公告)日：1979-05-16
申请号：JP12740777
申请日：1977-10-24
申请人： NIPPON STEEL CORP
发明人： WATANABE SEIICHI , KAWAMURA KOUJI , ICHIJIMA ISAMU , MIYAGAWA KAZUO
IPC分类号： H03H7/01 , H04L25/06
摘要： PURPOSE:To correct the distortion of the linearity or the amplitude by using the difference between the corrected signal which is the synchronous signal featuring a constant frequency and the signal obtained by delaying the phase of the corrected signal by about 180 deg.. CONSTITUTION:The corrected signal featuring the distortion is supplied to first LPF1 to remove the high-frequency component or the impulsive noise. Thus, waveform 1 is obtained. Then the cut-off frequency of second LPE3 is set nearly identical to the exciting frequency of the test coil in the eddy current test equipment to obtain output signal 2 featuring about 180 deg. phase difference to the input signal. Singnal 2 is then supplied to one terminal of differential amplifier 2 via voltage adjusting circuit 4. For signals 1 and 2 supplied to amplifier 2, the linear distortion parts (a) and (a)' caused at the switching rise time are removed as the in-phase component. At the same time, the amplitude distortion of the both signals emerge a little bit at the positive and negatice side each and is then removed away. Thus, signal 3 featuring the reduced distortion can be obtained.

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