| 摘要 |
PURPOSE:To prevent C/N deterioration in a code error rate characteristic and to attain miniaturization by applying, e.g., a surface acoustic wave element to at least one processing system for carrier component separated into plural systems so as to give a frequency spread characteristic in the delay time thereby keeping a prescribed phase difference. CONSTITUTION:An input reed screen electrode 15 and output read screen electrodes 16, 17 are arranged on a surface acoustic wave substrate 14. Further, the output reed screen electrodes 16, 17 are subjected to an aperture weighting so as to obtain a constant amplitude characteristic in a carrier frequency deviation band, and the group delay time at the center frequency of the electrode 17 is made coincident with that of the electrode 16 by making the main lobe position of the weighting of the reed screen electrode coincident with that of the electrode 16 so as to provide spread delay time in the frequency characteristic. Since the group delay time taug is expressed is equation (2), the gradient of the phase of VQ1, VQ2 at the center frequency is coincident and since the phase difference at the center frequency is 90 deg., the phase difference between the VQ1, VQ2 in the vicinity of the center frequency is constant (90 deg.).
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