EEVblog #381 - How Do Ultrasonic Delay Lines Work?

How do glass ultrasonic acoustic delay lines work? The kind used in PAL video recorders.
This is Part 3 of the Sony CCD Video 8 Camcorder Teardown.
PART 1: http://www.youtube.com/watch?v=HiXZQNOlnnk
PART 2: http://www.youtube.com/watch?v=iWOToL0KIe0
Service Manual: http://www.freeservicemanuals.info/en/servicemanuals/viewmanual/Sony/CCDV8AFEPART1/None/None/SERVICEMANUAL/
Forum Topic: http://www.eevblog.com/forum/blog-specific/eevblog-381-how-do-ultrasonic-delay-lines-work/

Delay line info:
http://www.morgantechnicalceramics.com/resources/piezoelectric-ceramics-properties-and-applications/ (chapter 6.9)

EEVblog Main Web Site:
http://www.eevblog.com
EEVblog Amazon Store:
http://astore.amazon.com/eevblogstore-20
Donations:
http://www.eevblog.com/donations/
Projects:
http://www.eevblog.com/projects/
Electronics Info Wiki:
http://www.eevblog.com/wiki/