Wideband beamforming using fan filter

Nishikawa, Kiyoshi; Yamamoto, Torn; Oto, K.; Kanamori, T.

doi:10.1109/iscas.1992.230137

Cited by 47 publications

(24 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hence, the spectra of 2D ST PWs, such that I9DOA < 900, are confined to the 2D fan- B. Broadband Beamforming of2D STPWs In [4], a broadband beamforming technique is proposei sampled 2D baseband ST PWs using a 2D FIR filter havi fan-shaped passband that closely encloses the linear RO the desired W2D (f, Ict) As shown in Fig. 2(a), the idea passband is defined by the acute-angled fan-shaped area lies between the straight lines f,-tan(Axis + )ft=0 fx tan(OAxis -£)5 t = 0, where (If fct) E R OAxis -tan' (sin(9DOA)).…”

Section: A Spatio-temporal Plane Waves and Their Spectramentioning

confidence: 99%

“…2(a), the idea passband is defined by the acute-angled fan-shaped area lies between the straight lines f,-tan(Axis + )ft=0 fx tan(OAxis -£)5 t = 0, where (If fct) E R OAxis -tan' (sin(9DOA)). The beam-direction of beamforming method in [4] is determined by f5Axis and beam-width by £. This method achieves impri directionality and reduced complexity, relative to broadband beamforming techniques [1], [2], [5] and [6].…”

Section: A Spatio-temporal Plane Waves and Their Spectramentioning

confidence: 99%

“…Therefore, a 2D fan filter may also be used fo selective 2D filtering of W2D B (X, Ct). However, to a temporal aliasing the temporal sample frequency fs must least 2fmaX Hz, where fmai = f + 0.5BW Hz [4].…”

Section: A Spatio-temporal Plane Waves and Their Spectramentioning

confidence: 99%

See 2 more Smart Citations

Broadband Beamforming of Bandpass Plane Waves using 2D FIR Trapezoidal Filters at Baseband

Gunaratne

Bruton

2006

APCCAS 2006 - 2006 IEEE Asia Pacific Conference on Circuits and Systems

View full text Add to dashboard Cite

A new method is proposed for broadband beamforming of two-dimensional (2D) spatio-temporal (ST) bandpass plane waves (PWs) using a complex 2D FIR filter structure having a trapezoidal-shaped passband at baseband and achieves the minimum possible temporal sampling rate for a given bandwidth. Experimental results show that this method is capable of enhancing 2D broadband bandpass ST PWs according to their directions of arrival (DOAs) in the presence of severe cochannel interference.

show abstract

Section: A Spatio-temporal Plane Waves and Their Spectramentioning

confidence: 99%

Section: A Spatio-temporal Plane Waves and Their Spectramentioning

confidence: 99%

See 1 more Smart Citation

Broadband Beamforming of Bandpass Plane Waves using 2D FIR Trapezoidal Filters at Baseband

Gunaratne

Bruton

2006

APCCAS 2006 - 2006 IEEE Asia Pacific Conference on Circuits and Systems

View full text Add to dashboard Cite

show abstract

“…Its design is performed in the two-dimensional frequency domain. By setting a fan filter for the spectrum of the desired sound on the two-dimensional frequency plane, an identical directive characteristic not dependent on the frequency with a low sidelobe level can be realized over the intended broad frequency range [7,8]. In this way, the problems of the delay-and-sum array and the adaptive array are resolved.…”

Section: Introductionmentioning

confidence: 99%

“…The beam direction of the array microphone is set to either the broadside or endfire direction of the array by choosing the passband shape of the fan filter [7,8]. In beamforming in the broadside direction of the array, a narrow beam can be obtained without increasing the order of the array or increasing the array length.…”

Section: Introductionmentioning

confidence: 99%

A design of array‐microphone system using directional microphones and two‐dimensional FIR filters

Naono¹,

Nishikawa

2006

Electron Comm Jpn Pt III

View full text Add to dashboard Cite

SUMMARYDelay-and-sum array microphones consisting of a linear array of microphones can achieve a sharp directivity at high frequencies. A disadvantage is that the directivity depends on the frequency. In order to resolve this problem, an array microphone using a fan filter has been proposed. However, in order to form a sharp beam at a low frequency, it is necessary to increase the filter order and the array length. In this paper, we report improvement of the directivity of an array microphone realizing a narrow beam with a relatively low order of the filter by means of a two-dimensional frequency domain design. Employing two microphones, a first-order pressure-gradient microphone is formed. The spacing of the microphones is set for high sensitivity and broad bandwidth in the operating frequency range. The amplitude characteristics are obtained in the two-dimensional frequency domain. These microphone units are placed along a line and are cascaded to a two-dimensional fan filter so that the load is distributed. In the proposed configuration, a cardioid microphone is cascaded with an axially symmetric fan filter in a configuration that forms a single broadside beam. Another configuration forms a single beam in the endfire direction by cascading the bidirectional microphone to a diagonally symmetric fan filter. Deterioration of the pressure-gradient microphone is compensated for by the two-dimensional FIR filter. As a result, the directional characteristics of the pressure-gradient microphone are reflected in the array microphone and a sharp directivity not dependent on the frequency is obtained over a wide frequency range.

show abstract

Wideband multi‐beam forming method using delayed array sensors and two‐dimensional digital filter

Nishikawa

2005

Electron Comm Jpn Pt III

View full text Add to dashboard Cite

SUMMARYIn this paper, a method is proposed for multi-beam forming of wideband signals by means of delay processors and two-dimensional fan filters. Only one axially symmetric two-dimensional fan filter is used. Multi-beam forming is carried out by multiplexing the delay processors for two-dimensional signals for each beam direction. The delay processing here corresponds to a rotation of the two-dimensional spectra in the two-dimensional frequency domain and provides a delay proportional to the sensor location to each sensor output. Since each delay is a fractional delay, a method of digital signal processing based on high-speed sampling and thinning is used for realization. A design method for multi-beam forming is given and a study of expanding the receiving angle range is carried out. It is shown that excellent multi-beam forming is possible if the method is used within an appropriate receiving signal range, although the beam width is slightly different depending on the beam direction. Finally, a difference of the method from multi-beam forming by the use of several two-dimensional fan filters is discussed. The positioning of this method and its effectiveness are clarified.

show abstract

Wideband beamforming using fan filter

Cited by 47 publications

References 4 publications

Broadband Beamforming of Bandpass Plane Waves using 2D FIR Trapezoidal Filters at Baseband

Broadband Beamforming of Bandpass Plane Waves using 2D FIR Trapezoidal Filters at Baseband

A design of array‐microphone system using directional microphones and two‐dimensional FIR filters

Wideband multi‐beam forming method using delayed array sensors and two‐dimensional digital filter

Contact Info

Product

Resources

About