A method to separate the transmitting signal and the receiving signal in FM-chirp pulse compression systems

We have developed a method of separating the transmitting and the receiving signals for FM-chirp pulse compression systems for use in intraductal ultr asonography. The method enables us to remove the unnecessary signals and to obtain a sufficient delay time. In this paper the following results are de scribed: 1) A method to separate the transmitting signal and the receiving signal with a long-time-duration was proposed using a flexible guided line. 2) A guided line suited for intravascular ultrasonography was constructed using the L(0, 3) mode of the Pocchammer-Chree wave propagating in a tapere d fused quartz rod. 3) A tentative result was obtained that a transmitting signal of a long-time-duration could be compressed to give a short pulse. 4 ) To use this guided line in intraductal ultrasonography, a method to desig n an optimum signal is necessary.