| 摘要 |
<p>PURPOSE:To improve the accuracy of an estimated value by estimating the additional impedance and position of an unbalanced point from the difference between measured values of input admittance before and after trouble occurs. CONSTITUTION:The balanced lines 1 in a terminal open state which have line length l0, a propagation constant (r), and specific impedance Z0 are connected to connection terminals 11 of an input admittance measurement part 2, the input admittance YOX before the lines 1 deteriorate is measured by an input admittance measurement part 3, and its data is stored in a measurement data storage part 4. Further, the constant (r), impedance Z0, and line length l0 are stored in a line constant storage part 6. Then the input admittance Y0 when additional impedance Z2 is added to the lines 1 at a distance l1 from the terminals 11 in parallel is measured by the measurement part 3 and its data is stored 4. A difference detector 5 reads input admittance values before and after the lines 1 deteriorate out of the storage part 4 to detect the difference Ym between the input admittance values. An arithmetic part 7 reads the constant (r), etc., out of the storage part 6 and processes them according to an expression to estimate the impedance Z2 and position l1 with which a calculated value Y is equal to the difference Ym, so that the result is outputted 8.</p> |
