Acoustic Surface Wave Research.
Semiannual rept. 1 Mar-31 Aug 71,
STANFORD UNIV CALIF MICROWAVE LAB
Pagination or Media Count:
New results are reported for wrap-around type delay lines, involving time delays of 2 milliseconds for passive lines without internal amplification, time delays of 20 milliseconds with internal surface wave amplifiers on large bismuth germanium oxide crystals, and demonstration of control of the threshold for noise buildup in such systems which is expected to lead to increased time delays in future devices. Internal experiments on a balanced-phase two-port configuration for wrap-around lines, designed to avoid bidirectional transducer losses, show the correct fringe pattern versus frequency. Results on electronically-tunable digital cross-correlation in a parametric surface acoustic wave device are presented which show improved conversion efficiency, reduced spurious levels, and good comparison of experiment and theory for Barker bi-phase codes up to 5 bits, and discrepancies in side lobe levels for larger number of bits, which are being investigated. Author
- Line, Surface and Bulk Acoustic Wave Devices
- Solid State Physics