| 摘要 |
A simple impedance measuring tool is provided for performing an accurate but inexpensive determination of impedance and assurance of an impedance match in an installation environment. The apparatus operates according to a method wherein the average instantaneous voltage on a transmission line is sensed based on the integration of a series of reflections stimulated by a pulse generator. The apparatus comprises a fast repetitive pulse generator, a fast comparator, a flip-flop and a means for integrating the output of the flip-flop to produce an output voltage which can be read by a simple low-cost meter such as a d.c. voltmeter. The output of the comparator is coupled to the data input of the flip-flop, which is driven at its clock input by a variable phase clock output of the pulse generator. The absolute time delay or phase determines the distance at which the measurement is to be taken.
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