| 摘要 |
PURPOSE:To obtain the echo signal with sufficient intensity in a simple constitution by attenuating one of the outputs of two neighbouring receiving elements by a specified amount, increasing the other by a specified amount, performing mixing process and the like, and correcting the receiving sensitivity. CONSTITUTION:Vibrators Vn...and V'n-1... forming a receiving element group EL are sequentially switched via switches. The signals are received by the neighbouring vibrators Vn... and V'n-1... and supplied to attenuators ATT1A... wherein the signals are attenuated from 100% to 0% of a ganged variable attenuator group GATT and to attenuators ATT2B... wherein the signals are increased from 0% to 100%. The outputs of the GATT are mixed and processed in mixers M1.... In this constitution, e.g., the output E1A of the attenuator ATT1A is virtually shifted to the output E2B, and the phase phi2 is shifted to phi1 by 3 steps. In this way, the vector component of the output is generated. This circuit is actually equivalent to a circuit wherein two additional vibrators are arranged between the neighbouring vibrators. Therefore, the receiving sensitivity can be corrected by the simple constitution, and the sufficiently intense echo signal can be formed. |
