We discuss the structural consideration of high-speed photodetectors used for optical communications, focusing on vertical illumination suitable device fabrication and coupling. fabricate an avalanche photodiode that can handle 100-Gbit/s four-level pulse-amplitude modulation (50 Gbaud) signals, pin photodiodes 100-Gbaud operation; both are fabricated with our unique inverted p-side down (p-dow...

In the most commonly used cochlear prosthesis systems, temporal features of sound are signaled by amplitude modulation of constant-rate pulse trains. Several convincing arguments predict that speech reception should be optimized by use of pulse rates > or approximately 2,000 pulses per second (pps) and by use of intracochlear electrode configurations that produce restricted current spread (e.g....

PURPOSE In an effort to restore functional form vision, epiretinal prostheses that elicit percepts by directly stimulating remaining retinal circuitry were implanted in human subjects with advanced retinitis pigmentosa RP). In this study, manipulating pulse train frequency and amplitude had different effects on the size and brightness of phosphene appearance. METHODS Experiments were performe...

A framework is proposed that allows for a joint description and optimization of both binary polar coding and 2 -ary digital pulse-amplitude modulation (PAM) schemes such as multilevel coding (MLC) and bit-interleaved coded modulation (BICM). The conceptual equivalence of polar coding and multilevel coding is pointed out in detail. Based on a novel characterization of the channel polarization ph...

Male Neoconocephalus robustus and Neoconocephalus bivocatus produce remarkably fast calls, with pulse rates of approximately 175-200 Hz. The temporal call patterns differ significantly between the two species. Male N. robustus produce calls with a single pulse rate of 200 Hz. In N. bivocatus, pulses are repeated with alternating periods, resulting in distinct pulse pairs: approximately 175 puls...

The performance analysis of free space optical communication (FSO) systems using relays and spatial diversity at the transmitter end is presented in this paper. The impact of atmospheric turbulence and attenuation caused by different weather conditions and geometric losses has also been taken into account. The effect of turbulence is modeled over a log-normal probability density function. We pr...

Direct current (DC)-link voltage ripple analysis is essential for determining harmonic noise and for DC-link capacitor design and selection in single-phase pulse-width modulation (PWM) inverters. This paper provides an extensive theoretical analysis of DC-link voltage ripple for full-bridge (H-bridge) inverters, with simulation and experimental verifications, considering a DC source impedance (...

An amplitude-optimised bit-edge equalisation (BEE) scheme is presented and compared with pulse-width modulation for mitigating intersymbol interference in high-speed backplane applications. With transmitter pre-coding and pre-emphasis, this BEE uses an adaptive LMS algorithm as a receiver error convergence engine by adjusting error derivation points. The optimality of the proposed BEE scheme is...

Cochlear implants stimulate the auditory nerve with amplitude-modulated (AM) electric pulse trains. Pulse rates >2,000 pulses per second (pps) have been hypothesized to enhance transmission of temporal information. Recent studies, however, have shown that higher pulse rates impair phase locking to sinusoidal AM in the auditory cortex and impair perceptual modulation detection. Here, we investig...

Temporal modulations in stimulus amplitude are essential for recognizing and categorizing behaviorally relevant acoustic signals such as speech. Despite this behavioral importance, it remains unclear how amplitude modulations (AMs) are represented in the responses of neurons at higher levels of the auditory system. Studies using stimuli with sinusoidal amplitude modulations (SAMs) have shown th...