| 摘要 |
Electrical filter circuits are tested by connecting test apparatus to the filter circuit inputs, without the need to connect to the filter outputs or to disconnect the outputs from a load. A signal generator of known source resistance applies a.c. signals successively over a range of frequencies to the filter circuit inputs, and a voltmeter monitors the voltage across the filter inputs. Different types of filter circuits have different characteristic shapes for the voltage/frequency curve, and processing is applied to the measured results by a computer to determine characteristics of the filter circuit, such as values of the individual sub-components of the filter circuit. An interactive process is applied to successively improve the accuracy of the component value determinations over a range of frequencies. Using the techniques described enables the insertion loss of the filter also to be readily calculated by the computer.
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