PubMed · 747153
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
N Hatfield, F Caccamise, P Siple. 1978. Deaf students' language competency: a bilingual perspective.. https://pubmed.ncbi.nlm.nih.gov/747153/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
This paper introduces directional microphones to adaptive array processing for hearing aid applications. Acoustic fixed arrays are designed to match a focused array gain pattern, while acoustic adaptive arrays are designed to attenuate interference noises with changing characteristics. However, as currently constructed, acoustic adaptive arrays cannot stay focused with a limited number of microphones available in a cosmetically acceptable hearing aid. In this paper, a technique is discussed that combines fixed and adaptive arrays in a system which enhances the desired signal while effectively attenuating interference speech and background noise. In particular, the design and performance of a directional adaptive least-mean-square (LMS) acoustic four-element array with a restricted geometry, where the array microphones are directional microphones, are examined. Simulations show that the directivity index of the directional adaptive array using four hypercardioid microphones is improved to between 8.6 and 11 dB. The array reduces the interference noises by 29.7 to 42.3 dB and provides a signal-to-noise ratio improvement of 11.5 to 12.2 dB over a single omnidirectional microphone. The sensitivity analysis is also discussed. It is concluded that the small size (four-element) microphone array can spatially filter interference noise effectively and so improve SNR performance significantly.
The effects of speechreading instruction were studied using a structurally planned training programme in two types of situations: in a face-to-face situation and by using videotapes viewed at home. Instruction was given only visually. Three speechreading tests were selected to monitor the efficacy of training: CID sentences. Helen questions and the tracking method. Two of the tests (CID and Helen) showed significant improvement in all three groups training speechreading. The tracking method, however, did not prove to be a reliable method for assessing the performance of a large group of subjects. The performances of the face-to-face groups and the video group did not differ significantly. The present study showed that training speechreading is advantageous and confirmed the effectiveness of tutored self-instruction at home.
This paper presents the development of a digital binaural hearing aid using Texas Instruments' floating point TMS320C3X digital signal-processing chip. The device is referred to as the Customized Universal Digital Listening System (CUDLS). CUDLS uses a wide bandwidth (up to 16 kHz) and incorporates speech enhancement (noise reduction) as an integral part of the device. It is capable of sampling up to two input speech channels at a variable sampling rate. We are currently using a sampling rate of 20 kHz for each channel. We have developed our own customized hardware and software to implement CUDLS in real time with zero processing delay. The system has been designed to make it easy for the therapist to modify its features.