In this paper a chaotic spiking neuron is presented and its response characteristics to various periodic inputs are analyzed. A return map which can analytically describe the dynamics of the neuron is derived. Using t...
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In this paper a chaotic spiking neuron is presented and its response characteristics to various periodic inputs are analyzed. A return map which can analytically describe the dynamics of the neuron is derived. Using the map, it is theoretically shown that a set of neurons can encode various periodic inputs into a set of spike-trains in such a way that a spike density of a summation of the spike-trains can approximate the waveform of the input. Based on the theoretical results, some potential applications of the presented neuron are also discussed. Using a prototype circuit, typical encoding functions of the neuron are confirmed by experimental measurements.
This brief presents a simple artificial spiking neuron and proposes its application to an A/D converter. Depending on the initial state, which is an analog input, the neuron can generate spike trains having various sp...
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This brief presents a simple artificial spiking neuron and proposes its application to an A/D converter. Depending on the initial state, which is an analog input, the neuron can generate spike trains having various spike position patterns. Based on spike position modulation, the spike train can be symbolized by a digital output. As a result, the analog input can be encoded into the digital output. Adjusting a reconfigurable parameter, the neuron can realize various encodings such as binary and Gray encodings. This brief also proposes a simple reconfigurable implementation circuit and experimentally confirms typical A/D conversion functions.
This paper presents a low-power analog circuit for signal processing on pulse coded signals using spatial mapping. By successively delaying a periodic pulse train, and correlating delayed copies of the input signal wi...
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This paper presents a low-power analog circuit for signal processing on pulse coded signals using spatial mapping. By successively delaying a periodic pulse train, and correlating delayed copies of the input signal with the input signal itself, the frequency component(s) are mapped spatially to output signals. The single delay line structure is then extended to a parallel structure with redundancy. In this way, we improve the signal-to-noise ratio. The design has been simulated and fabricated, and both simulation measurement results are presented, indicating the feasibility of the proposed methods.
In this paper, we have examined the possibility of incorporating pulse compression techniques into a conventional medical B-scan imaging scheme. Linear frequency modulation fm, one form of pulse coding among many othe...
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In this paper, we have examined the possibility of incorporating pulse compression techniques into a conventional medical B-scan imaging scheme. Linear frequency modulation fm, one form of pulse coding among many others, has been used in this study. With this approach, one can overcome current peak intensity limitations. A theoretical framework that includes medium propagation effects, transducer bandwidth and diffraction effects is presented, which could be used to examine the system point spread function under this imaging scheme. A prototype experimental set-up and signal processing are described and used for simple imaging tasks in attenuating and nonattenuating media. Analysis of the experimental point spread functions shows that resolution similar to conventional short pulse imaging can be achieved. However, the existence of large range side lobe levels usually associated with pulse compression processing can degrade contrast resolution in medical ultrasound. We have considered various different factors that can affect the range side lobe levels and examined their effect either experimentally or through simulations. The technique has the potential for improving signal-to-noise ratio (SNR), maximum penetration depth and resolution without exceeding peak intensity limitations. Some possible applications are discussed that merit further evaluation. Our work demonstrates the feasibility of this technique and presents a theoretical framework that can be used in future studies aimed at evaluating image quality, system performance, and possible artifacts under such an imaging scheme. (C) 1995 Academic Press, Inc.
1. A suitable technique was developed to chemically stimulate a single fungiform papilla of the frog tongue and record the action potentials from a single nerve fibre connected to the papilla. 2. Solutions of CaCl2, B...
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We have developed a method for measuring SR which combines the accuracy of DC measurement of basal SR level with the convenience gained from the AC coupling of SR responses for purposes of separating the total signal ...
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We have developed a method for measuring SR which combines the accuracy of DC measurement of basal SR level with the convenience gained from the AC coupling of SR responses for purposes of separating the total signal into basal SR level and SR responses. Our circuitry accomplishes (1) amplification of total DC signal, (2) post-amplification signal separation and display of SR responses and, on the same display channel, (3) pulse coding of basal SR.
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