| 摘要 |
PURPOSE:To set a compromised value for the main beam of a transmitting and receiving beam profile at a zero radiation angle and a side lobe by imparting a variable setting function of the amplitude of an exciting pulse voltage to a transmitter, and imparting a variable setting function for an amplitude to a receiving preamplifier. CONSTITUTION:A transmitting voltage VXPP is set with a transmitting-voltage setting signal 311 from a digital scan converter (DSC) 1A for a variable exciting- pulse-voltage amplitude circuit 40. A delayed transmitting timing pulse 302 is inputted into the circuit 40. The height of a pulse corresponding to an output VXFF is set. When an output VP of the circuit 40 is inputted into a transmitter 4, a current Ie flows through the secondary side of a transformer T1. A current which is proportional to the current Ie flows through the primary side of T1. Thus an ultrasonic wave probe 5 is excited. The intensity of the pressure of the sound wave emitted from the probe 5 is proportional to a voltage VK across both ends. VK is made variable by controlling a pulse height VP corresponding to VCC2. Meanwhile, the voltage at the secondary side of the transformer T1 is amplified in a variable gain type preamplifier, and a voltage level required for a processing circuit at the succeeding stage is obtained. |
