Hromadova Veronika, Brida Peter, Machaj Juraj
Faculty of Electrical Engineering and Information Technology, University of Zilina, 01026 Zilina, Slovakia.
Sensors (Basel). 2023 Sep 13;23(18):7852. doi: 10.3390/s23187852.
This paper addresses the limitations of using smartphones in innovative localization systems based on audio signal processing, particularly in the frequency range of 18-22 kHz, due to the lack of technical specifications and noise characterization. We present a comprehensive study on signal design and performance analysis for acoustic communication in air ducts, focusing on signal propagation in indoor environments considering room acoustics and signal behavior. The research aims to determine optimal parameters, including the frequency band, signal types, signal length, pause duration, and sampling frequency, for the efficient transmission and reception of acoustic signals for commercial off-the-shelf (COST) devices. Factors like inter-symbol interference (ISI) and multiple access interference (MAI) that affect signal detection accuracy are considered. The measurements help define the frequency spectrum for common devices like smartphones, speakers, and sound cards. We propose a custom signal with specific properties and reasons for their selection, setting the signal length at 50 ms and a pause time of 5 ms to minimize overlap and interference between consecutive signals. The sampling rate is fixed at 48 kHz to maintain the required resolution for distinguishing individual signals in correlation-based signal processing.
本文探讨了在基于音频信号处理的创新定位系统中使用智能手机的局限性，特别是在18 - 22 kHz频率范围内，这是由于缺乏技术规格和噪声特性所致。我们针对风道中的声学通信进行了信号设计和性能分析的全面研究，重点关注考虑房间声学和信号行为的室内环境中的信号传播。该研究旨在确定最佳参数，包括频段、信号类型、信号长度、暂停持续时间和采样频率，以便商用现货（COST）设备能够高效地发送和接收声学信号。我们考虑了诸如符号间干扰（ISI）和多址干扰（MAI）等影响信号检测准确性的因素。这些测量有助于确定智能手机、扬声器和声卡等常见设备的频谱。我们提出了一种具有特定属性的自定义信号，并说明了选择这些属性的原因，将信号长度设置为50毫秒，暂停时间设置为5毫秒，以尽量减少连续信号之间的重叠和干扰。采样率固定为48 kHz，以维持在基于相关性的信号处理中区分各个信号所需的分辨率。
