| 摘要 |
PURPOSE:To obtain a sufficient deviation required for communication and to attain frequency modulation with excellent modulation characteristic by using a signal being the integration of a modulation signal so as to control the center frequency and the group delay time of a variable phase equivalent device and passing the carrier through the variable phase equivalent device to obtain the frequency modulator. CONSTITUTION:A carrier generator 11 outputting a carrier, a variable phase equivalent device 21 whose center frequency is varied, and an integration device 13 are provided, the center frequency and the group delay time of the variable phase equivalent device 21 are controlled by using the signal being the result of the modulation signal integrated by the integration device 13, the carrier passes through the variable phase equivalent device 21 to obtain the frequency modulator. Thus, the frequency modulation is applied directly to the carrier regardless of the lockup time of the changeover of the carrier. Then a large delay time is obtained with less number of elements by the variable phase equivalent device 21 and an optional change in the delay time is given easily to the carrier. Thus, the deviation required for communication is obtained sufficiently and the frequency modulation with the excellent modulation characteristic is applied.
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