| 摘要 |
PROBLEM TO BE SOLVED: To correct a phase generated by a mechanical characteristic of an isolation amplifier or the like used for detecting a potential, and to allow accurate measurements, by controlling mutually an amplitude and a phase between two direct digital synthesizers (DDSs) to bring the potential in a reference potential point to a minimum, using the two direct digital synthesizers (DDSs), in a spectrum forcible polarization survey device. SOLUTION: In this spectrum forcible polarization survey device, with an impedance measuring object connected between a pair of coaxial cables in the four coaxial cables connected in parallel, and using a 4-terminal pair method for inputting a sine wave signal from one side thereof to measure an impedance, electromagnetic induction and electrostatic induction in the cable are active-controlled by digital-controlling the amplitude mutually and the phase between the DDSs, to minimize the potential in the reference potential point, using the two direct digital synthesizers, and the phase lag in circuit is controlled by utilizing the potential difference between the two direct digital synthesizers. COPYRIGHT: (C)2007,JPO&INPIT |
