Title :
A multi-DSP implementation of a broad-band adaptive beamformer for use in a hands-free mobile radio telephone
Author :
Claesson, I. ; Nordholm, S.E. ; Bengtsson, B.A. ; Eriksson, P.
Author_Institution :
Dept. of Telecommun. Theory, Lund Univ., Sweden
Abstract :
An implementation of a broadband adaptive array on a multiprocessor digital signal processing system for use in a hands free mobile radio telephone is described. This implementation of a five-microphone adaptive Griffiths-Jim array can handle FIR filters with up to 128 taps behind each microphone at a sampling rate of 8 kHz. The filter structure makes it possible to combine an adaptive array with a noise canceler. The near-field problem has been solved by using focusing, a speech-controlled adaptive algorithm, and a short hourglass. Preliminary measurements indicate a considerable potential for this technique in hands-free mobile telephony. The array gives a 20-30 dB suppression of a broadband jammer covering 300-1100 Hz, even with three reflecting walls surrounding the microphone.<>
Keywords :
computerised signal processing; interference suppression; microphones; mobile radio systems; 300 to 1100 Hz; 8 kHz; FIR filters; adaptive array; broad-band adaptive beamformer; broadband jammer; digital signal processing system; filter structure; five-microphone adaptive Griffiths-Jim array; focusing; hands-free mobile radio telephone; interference suppression; mobile telephony; multi-DSP implementation; multiprocessor system; near-field problem; noise canceler; reflecting walls; sampling rate; short hourglass; speech-controlled adaptive algorithm; Adaptive algorithm; Adaptive arrays; Adaptive filters; Digital signal processing; Finite impulse response filter; Land mobile radio; Microphone arrays; Noise cancellation; Signal sampling; Telephony;
Journal_Title :
Vehicular Technology, IEEE Transactions on
