title: Acoustic standing wave suppression using randomized phase-shift-keying excitations.
abstract: Recent papers have demonstrated that acoustic standing waves can be inhibited by frequency-modulated spread-spectrum excitation. An alternative method is studied here that is designed to be more practical for implementation in phased arrays. The method operates using phase-shift-keying (PSK), which introduces phase shifts into the driving signal to break wave symmetry. Sequential and random binary-PSK (BPSK) and quadrature-PSK (QPSK) excitations are studied in water, using a carrier frequency of 250 kHz and a time segment of 10 cycles. The resulting acoustic field is measured with a transducer inside a plastic-walled chamber and compared with continuous wave excitation. Results indicate that both the random BPSK and QPSK methods can reduce time-averaged spatial intensity variation caused by standing waves by approximately six times.
authors.forename: Sai Chun
authors.initials: SC
authors.lastname: Tang
authors.forename: Gregory T
authors.initials: GT
authors.lastname: Clement
mesh_terms: D000162:Acoustics; D010969:Plastics; D011312:Pressure; D013997:Time Factors
chemical_list: D010969:Plastics