COMPUTER CONTROL OF ANALOG DELAY LINES FOR B-MODE ULTRASONOGRAPHY

Publisher Summary This chapter discusses an improved phasing scheme taking advantage of reciprocity of lumped element analog delay lines. A functioning prototype electronically focuses a linear array of transducer elements through the use of a PDP-11 computer and lumped element analog delay lines. The overall width of the eight element array used in this system is 24 mm. Each element has a width of 1.0 mm and a height of 9.5 mm. The RP power amplifiers produce the power needed to excite the transducers. All the FORTRAN floating point calculated delays for a sector scan are stored as a file on a floppy disk. Through file manipulation, the user may either select a sector scan excitation format for the linear array or select to focus the linear array at any given scan point. The latter is used to obtain the focused transmit patterns of the array.