Patent ID: 8162838

Claim:
A non-transitory computer-readable medium comprising program code for causing a computer to perform a method of calculating a Doppler signal spectrum, the method comprising: receiving ultrasound echo signals; demodulating the ultrasound echo signals to obtain a Doppler signal; estimating parameters of the Doppler signal, the parameters comprising the strength, frequency center and frequency deviation of the Doppler signal; and resolving a predefined spectrum function of the Doppler signal based directly on the parameters, the spectrum function being at least a function of the parameters that characterize the power, mean angular frequency, and frequency deviation of the Doppler signal, where M is the length of the Doppler signal, R( 0 ) represents the power of the signal, and R( 0 ) is calculated as: R ⁡ ( 0 ) = ∑ i = 1 M - 1 ⁢ I i 2 + I i + 1 2 + Q i 2 + Q i + 1 2 2 .