Title :
Superdirective microphone array for a set-top videoconferencing system
Author_Institution :
PictureTel Corp., Andover, MA, USA
Abstract :
In set-top videoconferencing, the complete videoconferencing system fits unobtrusively on top of the television. The microphone sound pickup system is one of the most important functional blocks with constraints of small size, high performance, and low cost. Persons speaking several feet away from the system must be picked up satisfactorily while noise generated internally in the system by the cooling fan and hard drive, and noise generated externally from air conditioning and nearby computers must be attenuated. In this paper, a three microphone superdirective array is described which meets these constraints. An analog highpass and lowpass filter are used to merge two of the microphone signals to form a single channel, so that a single stereo A/D converter is required to process the three microphone signals. The microphone signals are then linearly combined so as to maximize the signal-to-noise ratio, resulting in nulls steered toward nearby objectionable noise sources
Keywords :
acoustic filters; acoustic noise; acoustic signal processing; acoustic transducer arrays; array signal processing; high-pass filters; low-pass filters; microphones; noise abatement; teleconferencing; analog highpass filter; lowpass filter; microphone signals; microphone sound pickup system; objectionable noise sources; set-top videoconferencing system; signal-to-noise ratio; stereo A/D converter; superdirective microphone array; Acoustic noise; Cooling; Cost function; Drives; Microphone arrays; Noise generators; Signal processing; Signal to noise ratio; TV; Teleconferencing;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 1997. ICASSP-97., 1997 IEEE International Conference on
Conference_Location :
Munich
Print_ISBN :
0-8186-7919-0
DOI :
10.1109/ICASSP.1997.599612