| 摘要 |
PURPOSE: To provide a a circuit which can control a gain dynamically for each channel of a multichannel system, reduce a time variation in the aperture size of channels within a specified range and maintain a desired apodization profile. CONSTITUTION: A circuit in the invention is provided with a means of controlling a gain for each channel, a means of generating multiple basic time-varying functions, a means of obtaining a signal having dynamic gain characteristics concerning prescribed channels necessary for an apodization profile by weighting appropriately at least selected functions of the basic functions and combining by adding the weighted functions, and a means of supplying an appropriate signal to control the gain control means concerning each channel.
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