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US 2003/0164710 A1Published application
Method for measuring fault locations in high frequency cables and lines
AssigneeT-Mobile Deutschland GmbH
InventorRolf Schmidt
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AssigneeT-Mobile Deutschland GmbH
InventorRolf Schmidt
Estimating the term…
The invention relates to a method for measuring fault locations in high frequency cables and lines. A signal with the frequency f0 and a level a0 is emitted from the source. This signal is split up in the splitter and is routed to the same parts in the test piece (DUT=device under test) and to a sink. The signals of the source and the returning wave of the DUT are added, whereby the result of this addition is a signal with the frequency f0 and an amplitude a1. The value of the frequency f0 is changed, and the amplitude of the newly generated sum signal is, in turn, recorded, whereby this is repeatedly carried out in an appropriate frequency domain (Span). An inverse Fourier transformation is applied to the measured values and transforms the signals from the frequency domain into the time domain. The transition point, which appears as the defined peak in the time diagram, can, as a result, be found located while taking the shortening factor into account.
Method for measuring fault locations in high frequency cables and lines, characterized by the steps:
Method according to one of the preceding claims, characterized by the fact that a first calibration measurement with a SHORT is performed at the end of the measuring cable (4), the measured values are stored in an array as( ), submitted to an inverse Fourier's transformation and stored in an array zts( ).
Method according to one of the preceding claims, characterized by the fact that a second calibration measurement with a LOAD is performed at the end of the measuring cable (4), the measured values are stored in an array zl( ), submitted to an inverse Fourier's transformation and stored in an array ztl( ).
Method according to one of the preceding claims, characterized by the fact that the measured values ztd( ) are multiplied with a window function window( ).
Method according to one of the preceding claims, characterized by the fact that the line impedance and the shortening factor of the test piece (5) are considered in the measured values.
Method according to one of the preceding claims, characterized by the fact that the line impedance of the test piece (5) along the measured frequency range is determined by interpolation by means of a cubic polynomial on the basis of some few measuring points.
Dependencies are inferred from the claim text.