A mobile radio transceiver comprising a hands-free facility, which hands-free facility combines at least two acoustic input signals to produce an output signal, and an adaptive filter is provided for filtering the combined output signal. To achieve an improved speech quality, a high-pass filter is provided for filtering the acoustic input signals.
A system and process for estimating the time delay of arrival (TDOA) between a pair of audio sensors of a microphone array is presented. Generally, a generalized cross-correlation (GCC) technique is employed. However, this technique is improved to include provisions for both reducing the influence (including interference) from correlated ambient noise and reverberation noise in the sensor signals prior to computing the TDOA estimate. Two unique correlated ambient noise reduction procedures are also proposed. One involves the application of Wiener filtering, and the other a combination of Wiener filtering with a G.sub.nn subtraction technique. In addition, two unique reverberation noise reduction procedures are proposed. Both involve applying a weighting factor to the signals prior to computing the TDOA which combines the effects of a traditional maximum likelihood (TML) weighting function and a phase transformation (PHAT) weighting function.
An electronic device can be operated to detect noise, such as wind noise. A microphone signal is generated by a microphone. Autocorrelation coefficients are determined based on the microphone signal. Gradient values are determined from the autocorrelation coefficients. The presence of a noise component in the microphone signal is determined based on the gradient values.
A method and arrangement for telecommunication comprises that it is detected (120) whether an incoming signal is speech or background noise, and encoding (100, 110) and transmitting parameters characterising the incoming signal. In or before (103) in the encoding of the background noise, parameters are produced, which represent background noise having increased low frequency components. Thus, the incoming signal can be subjected (103) to a frequency tilting operation. The degree of increasing the low frequency components is determined by the maximum long term correlation of the incoming signal. This method and arrangement provides a better generation of comfort noise, when the input signal comprises low frequency sinusoids, such as engine noise from cars and trams.
In the method according to the invention a signal processing unit receives signals from at least two microphones worn on the user's head, which are processed so as to distinguish as well as possible between the sound from the user's mouth and sounds originating from other sources. The distinction is based on the specific characteristics of the sound field produced by own voice, e.g. near-field effects (proximity, reactive intensity) or the symmetry of the mouth with respect to the user's head.
A wireless communication device receives audio data from a base station via a radio frequency (RF) communication link (i.e., a forward link) and transmits audio data to the base station via the RF communication link (i.e., a reverse link). The wireless communication device uses the inherent functionality of the reverse link, including an audio input device (120) to determine whether the wireless communication device is operating in a high noise environment. A signal analyzer (124) analyzes the audio signal on the reverse link and determines whether the ambient noise level exceeds predetermined threshold. If so, the signal analyzer (124) activates a filter (126) to filter the audio signal being provided to an audio output transducer (122). Band limiting the audio signal provided to the audio output transducer (122) improves intelligibility of the audio signal in the presence of noise.
