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Biomedical subjects

J J Paulos

Publications and source records attributed to J J Paulos.

2 recordsLinked to original sources

New strategies for improving speech enhancement.

We describe two design strategies that could substantially improve the performance of speech enhancement systems. Results from a preliminary study of pulse recovery are presented to illustrate the potential benefits of such strategies. The first strategy is a direct application of a non-linear, adaptive signal processing approach for recovery of speech in noise. The second strategy optimizes performance by maximizing the enhancement system's ability to evoke target speech percepts. This approach may lead to better performance because the design is optimized on a measure directly related to the ultimate goal of speech enhancement: accurate communication of the speech percept. In both systems, recently developed 'neural network' learning algorithms can be used to determine appropriate parameters for enhancement processing.

Algorithms

A monolithic patch-clamping amplifier with capacitive feedback.

Patch-clamping is an established method for directly measuring ionic transport through cellular membranes with sufficient resolution to observe open/close transitions of individual channel molecules. This paper describes an alternative technique for patch-clamping which uses a capacitor as the transimpedance element. This approach eliminates bandwidth and saturation limitations experienced with resistive patch-clamping amplifiers. A complete monolithic design featuring an on-chip operational amplifier, a capacitor array with gain-ranging from 30 pF down to 0.03 pF, and reset and gain ranging switches has been fabricated using 5 microns CMOS technology. It is shown that the voltage noise of the CMOS operational amplifier limits the overall noise performance, but that performance competitive with conventional instruments can be achieved over a 10 kHz bandwidth, at least for small input capacitances (less than or equal to 5 pF). Results are presented along with an analysis and comparison of noise performance using both resistive and capacitive elements.

Amplifiers, Electronic