| 摘要 |
PROBLEM TO BE SOLVED: To prevent a high doppler frequency (PRF) being misidentified as a low doppler frequency or a blood flow direction being determined by mistake due to the occurrence of aliasing, when a pulse repetition frequency is equal to or greater than +/-2. SOLUTION: N number of Doppler signals are transmitted/received at a transmission/reception unit at a pulse repetition frequency, a first mean frequency of a Doppler signal is calculated from an n-th outputted Doppler signal and an (n-1)th outputted Doppler signal, a second mean frequency of a Doppler signal is calculated from the n-th outputted Doppler signal and an (n-k)th outputted Doppler signal, a first signal processing to decrease the influence of noises when a doppler frequency is estimated and a second signal processing to compensate aliasing of a Doppler signal are performed from the first and second mean frequencies, and a Doppler mode image is formed from the signal processed Doppler signals. COPYRIGHT: (C)2009,JPO&INPIT |
