| 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 its maximum value and minimum value, and frequencies corresponding to them. CONSTITUTION:The high frequency signal source 7 whose frequency is variable is connected to the input end of a cable 1 for measurement which is long enough as compared with the wavelength of a measurement frequency, and the load 6 to be measured is connected to the terminal of the cable 1. Then, the frequency of the signal source 7 is varied gradually and the detection output voltage of a reflected wave from the load 6 is read and stored by a voltmeter 10 at the cable input terminal. When the length and characteristics of the cable 1 are calibrated, the terminal of the cable 1 is short-circuited, and frequency of the signal source 7 is varied, and a detection voltage is measured and store similarly, thereby finding the coefficient of reflection and impedance of the load 6 from the maximum and minimum values of both measured voltages and frequency corresponding to the minimum voltage. A computer and a CRT are incorporated in this device and the coefficient of reflection is displayed on a Smith chart on a CRT with polar coordinates, so that the impedance is readable directly.
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