| 摘要 |
PURPOSE:To obtain a simple, inexpensive measuring instrument by making the frequency of a signal source variable, finding voltage variation between the connection of a load to be measured with a cable end and its short- circuiting, and measuring a maximum value and a minimum value, and frequencies corresponding to them. CONSTITUTION:The high frequency signal source 7 whose frequency is variable is connected through a directional coupler 9 to the input end of a cable 1 for measurement which is long enough as compared with the wavelength of a measurement frequency. Further, the load 6 to be measured is connected to the other end, and a voltmeter 10 which has a detector is connected to the output end of the auxiliary arm of the coupler 9. Then, the frequency of the signal source 7 is varied gradually to read and store the detection output voltage of a reflected wave from the load 6. Then, the terminal of the cable 1 is short- circuited, the frequency of the signal source 7 is varied, and a detection voltage is measured and stored similarly, thereby finding the impedance of the load 6 from the maximum and minimum values of both measured voltages and frequencies corresponding to them. This measurement is taken only by measuring the absolute value of the voltage at one place, so the device is reduced in cost.
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