Patent ID: 6106462
Filing Date: 2000-08-22
Classification: G01S,H03H

Abstract:
An ultrasonic apparatus for transmitting an ultrasonic wave to an object to assist in making a diagnosis for the object on the basis of a reflected wave from the transmitted wave, comprising:transmission means for transmitting the ultrasonic wave to the object:reception means for receiving the reflected wave by the object and converting the reflected wave into an electrical signal;filter means for filtering the electrical signal; andcontrol means for controlling a filter characteristic of said filter means,wherein said filter means includes at least two connected LC filters, each including a capacitor including a variable capacitance diode and an inductor,said control means adjusts a capacitance of at least one of the variable capacitance diodes in accordance with a depth to the object so as to control the filter characteristic of said filter means,a value of the capacitor including the variable capacitance diode is optimized around a lower limit and an upper limit within a variable range of a cutoff frequency of said filter means,a value of the inductor is opimizied around a median within the variable range, anda high-frequency side of the cutoff frequency is variable within a range of 20 MHZ or more.