Medical ultrasonic Doppler imaging is one of the most important domains of modern medical
imaging technology. The application of coded excitation technology in medical ultrasonic Doppler
imaging system has the potential of higher SNR and deeper penetration depth than conventional
pulse-echo imaging system, it also improves the image quality, and enhances the sensitivity of feeble
signal, furthermore, proper coded excitation is beneficial to received spectrum of Doppler signal.
Firstly, this paper analyzes the application of coded excitation technology in medical ultrasonic
Doppler imaging system abstractly, showing the advantage and bright future of coded excitation
technology, then introduces the principle and the theory of coded excitation. Secondly, we compare
some coded serials (including Chirp and fake Chirp signal, Barker codes, Golay's complementary
serial, M-sequence, etc). Considering Mainlobe Width, Range Sidelobe Level, Signal-to-Noise Ratio
and sensitivity of Doppler signal, we choose Barker codes as coded serial. At last, we design the coded
excitation circuit. The result in B-mode imaging and Doppler flow measurement coincided with our
expectation, which incarnated the advantage of application of coded excitation technology in Digital
Medical Ultrasonic Doppler Endoscope Imaging System.