| 摘要 |
PURPOSE:To prevent disturbance of a picture due to noise by a method wherein, when the speed of a moving body is delayed and a ratio of noise contained in a code analyzed by an analyzer is high, instead of the code, an average code is used to display speed distribution of the moving body. CONSTITUTION:A power comparator 311 inputs a power (p) from a color Doppler analyzer 121 and compares the power with given threshold p0 to input a result to a frequency selecting circuit 313. A frequency (f) is inputted from the analyzer 121 to the selecting circuit 313, and it is selected according to the comparing result of the comparator 311 whether the frequency (f) is outputted as it is or after it is reduced to zero, and a result is inputted to a frequency averaging circuit 315. The circuit 315 determines an average frequency in a given time, and selects a code (s), analyzed by an analyzer 121, when the average frequency exceeds a given threshold. Based on the code and the average frequency, speed distribution of a moving body is displayed. When it is below the given threshold, an average code calculated by a code averaging circuit 321 is selected, and based on the average code and an average frequency, speed distribution of the moving body is displayed. When the speed of the moving body is delayed and a ratio of noise contained in the code (s) is high, an average code is selected instead of the code. |
