REGULAR PAPER Increasing Bandwidth of Ultrasound Radio Frequency Echoes Using Wiener Filter for Improvement of Accuracy in Measurement of Intima–Media Thickness Sho Kageyama, Hideyuki Hasegawa, and Hiroshi Kanai Jpn. J. Appl. Phys. 52 (2013) 07HF04 Reprinted from # 2013 The Japan Society of Applied Physics