| 摘要 |
PURPOSE:To obtain an orthogonal modulator with a wide band by correcting the frequency characteristic of a mixer or a hybrid or the like giving disturbance to wide band processing depending on the deviation of the ideal characteristic measured in advance at each frequency band. CONSTITUTION:An oscillated frequency of a carrier oscillator 3 is controlled by an external switch signal 9 and changed in the frequency step, then the output frequency of the oscillator 3 is recognized by the switch signal 9. Thus, the switch signal 9 is inputted to a 1st and 2nd ROMs 101, 102 as each frequency band information, the corresponding correction quantity is outputted from the ROMs 101, 102, and the deviation from the ideal characteristic of the orthogonal modulator at each frequency band is corrected by a phase shifter 104 for the phase and by an attenuator 103 for the amplitude. For example, as to the phase correction, the phase deviation ALPHAtheta from the ideal 90 deg. has only to be corrected by the phase shifter 104. Thus, the output 8 is subject to orthogonal modulation over the wide band.
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