The inability of cochlear implant (CI) users to accurately localize sound sources poses daily safety risks and impedes social communication. While future augmented reality (AR) glasses are an ideal platform for delivering real-time visual and tactile assistive cues, their potential is hampered by a critical knowledge gap: how to design effective, non-distracting interfaces for this specific user group. To address this, we introduce a novel methodological approach using a virtual reality (VR) platform with high-fidelity color passthrough. This platform functions as an ecologically valid yet fully controllable testbed that faithfully simulates a future AR experience. Within this environment, we conducted a within-subjects study with 16 CI users to systematically evaluate three non-auditory cueing strategies: 1) Visual-Only, using color-coded peripheral widgets; 2) Tactile-Only, via a custom 8-channel vibrotactile array; and 3) a combined visuo-tactile Multimodal approach. We rigorously measured localization accuracy (absolute angular error), reaction time, front-back confusion rates, and subjective cognitive load (NASA-TLX). Our results reveal a critical performance-load trade-off: the multimodal strategy yielded the highest accuracy, reducing the mean error from 85.3° to 8.1°, but also imposed the greatest cognitive load. Conversely, the tactile-only strategy offered a compelling balance, significantly improving performance while being rated as the least cognitively demanding. From this analysis, we derive foundational insights and a set of evidence-based design guidelines to inform the creation of more effective and usable auditory awareness systems on future AR platforms.

This brief analyses the causes of amplitude and phase errors in digital step attenuators (DSAs), and proposes two novel structures, namely, the series inductive compensation structure (SICS) and the small-bit compensation structure, to reduce these two kinds of errors. A 6-bit DSA with ultrawideband, low insertion loss, and high accuracy is presented, which has an area of only 0.51 mm2 and shows an attenuation range of 31.5 dB in 0.5 dB steps. Measurements reveal that the root-mean-square (rms) amplitude and phase errors for the 64 attenuation states are within 0.18 dB and 8°, respectively. The insertion loss is better than 2.54 dB, and the input 1 dB compression point (IP1 dB) is better than 29 dBm. To the best of our knowledge, this chip presents the highest attenuation accuracy, the lowest insertion loss, the best IP1 dB, and a good matching performance in the range of 2–22 GHz using the 0.25-$\mu $m GaAs p-HEMT process.

The accuracy of noninvasive oxygen saturation (SpO2), which is defined by the measurements based on photoplethysmographic (PPG) signals, is intensively affected by motion artifacts (MAs) and low perfusion. This study introduces a novel approach called ESPRIT-MLT to measure SpO2when such interferences are present. In contrast to previous studies, the work focuses on the harmonic model of the PPG signal and the probability model of results from harmonic analysis. The optimized parametric ESPRIT method is applied to improve the accuracy of harmonic power estimation, and the maximum likelihood SpO2tracking (MLT) technique is proposed to track the most probable uncontaminated harmonic of heart rate frequency. We construct an evaluation platform for testing the proposed method via generated signals and subject tests. Compared with the nonparametric periodogram method, the probability of correct harmonics being found is improved by 18.7% or 19.7%, when the signal is contaminated by motion artifacts or affected by low perfusion, respectively. In comparison with the reference methods, the proposed ESPRIT-MLT method exhibits a lower average root mean square error (RMSE) (1.17%) in the simulation using an MA-contaminated PPG signal, and a lower RMSE (2.70%) in the simulation using an extremely low (0.05%) perfusion index. A comprehensive subject test that consists of 4 activities and 20 subjects shows an average RMSE of 0.84% (± 0.44%). Furthermore, the time-efficiency is optimized to be adaptable with wearable devices. Therefore, the proposed method has potential in enhancing the performance of clinical pulse oximetry and wearable SpO2measurement devices for daily use.