Abstract
Beamforming, or spatial filtering, is one of the simplest methods for discriminating between different signals based on the physical location of the sources. Because speech is a very wideband signal, covering some four octaves, traditional narrowband beamforming techniques are inappropriate for hands-free speech acquisition. One class of broadband beamformers, called constant directivity beam-formers, aim to produce a constant spatial response over a broad frequency range. In this chapter we review such beamformers, and discuss implementation issues related to their use in microphone arrays.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsPreview
Unable to display preview. Download preview PDF.
References
B.D. Van Veen and K.M. Buckley, “Beamforming: A versatile approach to spatial filtering,” IEEE ASSP Mag., vol. 5, no. 2, pp. 4–24, Apr. 1988.
T.D. Abhayapala, R.A. Kennedy, and R.C. Williamson, “Nearfield broadband array design using a radially invariant modal expansion,” J. Acoust. Soc. Amer., vol. 107, no. 1, pp. 392–403, Jan. 2000.
J.L. Flanagan, D.A. Berkeley, G.W. Elko, J.E. West, and M.M. Sondhi, “Autodirective microphone systems,” Acustica, vol. 73, pp. 58–71, 1991.
W. Kellermann, “A self-steering digital microphone array,” in Proc. IEEE Int. Conf. Acoust., Speech, Signal Processing (ICASSP-91), 1991, vol. 5, pp. 3581–3584.
F. Khalil, J.P. Jullien, and A. Gilloire, “Microphone array for sound pickup in teleconference systems,” J. Audio Eng. Soc., vol. 42, no. 9, pp. 691–700, Sept. 1994.
J. Lardies, “Acoustic ring array with constant beamwidth over a very wide frequency range,” Acoust. Letters, vol. 13, no. 5, pp. 77–81, 1989.
R. Smith, “Constant beamwidth receiving arrays for broad band sonar systems,” Acustica, vol. 23, pp. 21–26, 1970.
M.M. Goodwin and G.W. Elko, “Constant beamwidth beamforming,” in Proc. IEEE Int. Conf. Acoust., Speech, Signal Processing (ICASSP-93), 1993, vol. 1, pp. 169–172.
J.H. Doles III and F.D. Benedict, “Broad-band array design using the asymptotic theory of unequally spaced arrays,” IEEE Trans. Antennas Propagat., vol. 36, no. 1, pp. 27–33, Jan. 1988.
A. Ishimaru, “Theory of unequally-spaced arrays,” IRE Trans. Antennas Propagat., vol. AP-10, pp. 691–702, Nov. 1962.
A. Ishimaru and Y.S. Chen, “Thinning and broadbanding antenna arrays by unequal spacings,” IEEE Trans. Antennas Propagat., vol. AP-13, pp. 34–42, Jan. 1965.
T. Chou, “Frequency-independent beamformer with low response error,” in Proc. IEEE Int. Conf. Acoust., Speech, Signal Processing (ICASSP-95), Detroit, USA, May 1995, pp. 2995–2998.
S. Haykin and J. Kesler, “Relation between the radiation pattern of an array and the two-dimensional discrete Fourier transform,” IEEE Trans. Antennas Propagat., vol. AP-23, no. 3, pp. 419–420, May 1975.
J.S. Marciano Jr. and T.B. Vu, “Reduced complexity beam space broadband frequency invariant beamforming,” Electronics Letters, vol. 36, no. 7, pp. 682683; Mar. 2000.
D.B. Ward, R.A. Kennedy, and R.C. Williamson, “Theory and design of broadband sensor arrays with frequency invariant far-field beam patterns,” J. Acoust. Soc. Amer., vol. 97, no. 2, pp. 1023–1034, Feb. 1995.
D.B. Ward, R.A. Kennedy, and R.C. Williamson, “FIR filter design for frequency-invariant beamformers,” IEEE Signal Processing Lett., vol. 3, no. 3, pp. 69–71, Mar. 1996.
C. Winter, “Using continuous apertures discretely,” IEEE Trans. Antennas Propagat., vol. AP-25, pp. 695–700, Sept. 1977.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2001 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Ward, D.B., Kennedy, R.A., Williamson, R.C. (2001). Constant Directivity Beamforming. In: Brandstein, M., Ward, D. (eds) Microphone Arrays. Digital Signal Processing. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-04619-7_1
Download citation
DOI: https://doi.org/10.1007/978-3-662-04619-7_1
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-07547-6
Online ISBN: 978-3-662-04619-7
eBook Packages: Springer Book Archive