Agilent 1998-08 free download

File name 1998-08.pdf

ourna HEWLE T T -PACK A R D rhfiW HEW LE TT IL': ~ PACKAI=l D Durn H EWLE T T - PA C K A R D The heart of an ultrasound Imaging system is the electroscoustic transducer; a device that converts electrical signalsinto a focusedmechanicalwave and reconverts reflected mechanical echoes from organs and tissue for real-time image construction. Small, calibrated transducers called hydrophones are usedto measure the acoustic outputof the transducers usedin these systems. The first article in this issue describes a hydrophone developed by HP that has a spot diameterof 50micrometers and a bandwidth greater than 150 MHz, enabling it to characterize medical imaging rransducers with operating fre- ouencies exceeding 20MHz. Measurement accuracy for HP optical power meters and other optical The 150 -MH z-b a n d w i d t h m e m b r a n e hydrophone instruments is the main theme in the next article. TI?e article elso contains desc r i b e d on page 6. an overview on the theory of measurement. The si g n a l is generated by a 20-MHz f o c u sed Hewlett-Packard holds severalinternal conferences each yearto sllow HP ult r a s ound t r a n sdu c e r scientists and engineers to share such things as best practices and research driv ing water into a non- activities, We have five papers from the 1997 conferencesponsored by engi- li n e a r st at e . See page 11 neers from HP's integrated circuit R&D community. to identify the parts on this hydrophone. Improvements in simulation and verification toots for Ie design are the main topics of the first two oi these 8 rticle s. The first describes the development Volume 49