| 摘要 |
PURPOSE:To set filtering characteristic corresponding to the band area of an echo signal extending from a shallow part to a deep part, or with the frequency of an ultrasonic wave to be used by providing a means which varies passing band limitation at a filter means. CONSTITUTION:The echo signal received at an oscillator E1 is inputted to an adder SIGMA via the filter means F1 and a sampling delay means D1 after being amplified with an amplifier A1. At this time, the passing band of the echo signal is variably controlled with a time at the filter means F1, and an unrequired component is eliminated from the echo signal at entire depth. For example, assuming the bands of a shallow part echo signal as fH1-fH2, and that of a deep part echo signal as fL1-fL2, the passing band of the echo signal of the filter means with variable band is varied as shown in arrow head. At this time, it is possible to respond to plural probes by setting the filtering characteristic variably corresponding to the frequency of each ultrasonic wave using the filtering characteristic. |
