| 摘要 |
PURPOSE:To decrease the likage of noise behind a signal amplifier by setting a gain control curve so as to be low gain only for an area where the noise is generated on a received echo signal. CONSTITUTION:A transmitting pulse to be generated by a transmission circuit 2 drives an oscillator in a probe 1 and radiates an ultrasonic wave to a reagent. An ultrasonic echo signal to be reflected from the reagent is converted into an electric signal by the oscillator of the probe 1 and processed by the two systems of first and second receiving phase matching circuits 3 and 4. In the process of the processing, the noise by a focus switching control signal is generated in a focused signal in the first and second receiving phase matching circuits 3 and 4. The echo signals outputted from the first and second receiving phase matching circuits 3 and 4 are inputted to signal amplifiers 5 and 6, which are controlled by the gain control curve sent from a gain control curve generating circuit 8, and the noise of the focused signal is removed. |
