Nonlinear coded excitation method for contrast imaging

Bursts are more effective than short pulses in generating strong response from an ultrasound contrast agent bubble. We propose chirped excitation signals in combination with a 2/sup nd/ harmonic compression technique to improve the signal strength from the contrast agent. Results show good compression if the excitation chirp is band-limited. Range side lobes appear in the compressed signal if there is overlap between the harmonics and the fundamental.