| 摘要 |
PURPOSE:To execute the phasing processing of high time accuracy by a circuit means of a small scale by controlling the delay quantity of an ultrasonic receiving signal of a multichannel by a storage device for executing write and read- out operations by a prescribed clock and the phase control of a reference signal and executing the phasing processing. CONSTITUTION:A receiving signal R from a transducer 1 is applied to a multiplier 2. Such a receiving signal R is multiplied by a reference signal G whose phase is controlled by a multiplier 2. By the multiplication, a high frequency component of the sum of frequencies of both the signals and a difference frequency component are generated, but by allowing them to pass through a low- pass filter 3, an output signal S of 3 becomes only the difference frequency component. This output signal S is stored in a storage device 4 at a prescribed clock interval T. In addition to the time adjustment of the interval T by control data ND, a precise time adjustment except T is executed by time control of the reference signal G. By adding the receiving signals brought to time adjustment, respectively at every receiving signal channel, phasing aligned with a wave front of a reflected acoustic wave from a point of desired depth and direction is performed. |
