| 摘要 |
PROBLEM TO BE SOLVED: To secure isolation between ON and OFF of a transmission pulse in simple configuration and to satisfy a specification required for suppressing an unwanted signal on a time base. SOLUTION: The isolation between the ON and OFF of an IF pulse generated by an IF pulse generator 21 is 30 dB. Besides, the unwanted signal, which can not be removed with a band pass filter, on the time base is generated by a heat noise or the like. When an RF pulse is turned on/off by synchronizing first and second RF coaxial switches 25 and 26 with the rise/fall of the IF pulse after RF pulse conversion, the isolation of 40 dB is secured so that the overall isolation of 80 dB can be secured. Thus, multiple steps of RF coaxial switches are connected to match the required isolation and ON/OFF is controlled to contain the IF pulse so that the required specification can be satisfied in a simple configuration.
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