| 摘要 |
PURPOSE:To obtain the B mode image of high S/N and high resolution by providing a frequency analyzer for analyzing the frequency component of a pulse echo signal in order to change the passing frequency band of a band pass filter to the band of a received pulse echo signal. CONSTITUTION:In a frequency analyzer 11, the data of several pieces of scanning lines is extracted with regard to a pulse echo signal, and the signal of the extracted scanning lines is brought to FET operation. As for the result of calculated frequency analysis, the measuring part is different by each scanning line used for the operation, therefore, frequency band data of the same load of each scanning line are averaged by an adder 7, respectively, and based on the averaged frequency band data, a passing data of a band pass filter 6 is controlled. Subsequently, to the band pass filter 6 whose passing band is set to the band of the pulse echo signal, a pulse echo signal is inputted from a pre-amplifier 5 and passes therethrough, by which a noise component except a signal band is filtered, and the S/N is improved. The pulse echo signal from which noise component is eliminated is inputted as a luminance signal to a CRT 8 through a log amplifier 7, and displayed as a B mode image. |
