| 摘要 |
PROBLEM TO BE SOLVED: To perform the multi-stage transmission focusing with appropriate transmission energy. SOLUTION: A code modulation processing part 10 generates a transmission pulse based on a pulse compressing process. A transmission beam former 12 generates a transmission signal based on the transmission pulse outputted from the code modulation processing part 10. The transmission beam former 12 forms three transmission beams-an F1 transmission beam, an F2 transmission beam and an F3 transmission beam-in respective beam directions 30 corresponding to a short distance focal point F1, a medium distance focal point F2 and a long distance focal point F3 respectively. The three beams are transmitted in the order of the F1 transmission beam, the F2 transmission beam and the F3 transmission beam, and the transmission energy is set larger as the depth of the transmission focal point is deeper. COPYRIGHT: (C)2005,JPO&NCIPI
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