Synchronization and sampling in wireless adaptive signal processing systems

This paper deals with the synchronization in wireless adaptive signal processing systems. Wireless communication offers high flexibility, however, the distributed structure of wireless systems requires the synchronization of the subsystems. The synchronization becomes particularly important if the signal bandwidth is in the kHz range, and it is inevitable in distributed control systems. The demand on the synchronization is presented through the introduction of a wireless active noise control system. In this system wireless sensors (microphones) receive the signal, and the main signal processing algorithm is implemented on a central unit which produces the signal for the actuators (loudspeakers). In spite of the special application, the system has a general structure, so the results are valid for other adaptive systems. First a PLL like algorithm is described for the synchronization of the sampling in a wireless real-time signal processing system, then a higher-level synchronization is introduced for a distrib uted Fourier-analyzer based noise control system. The effectiveness of the algorithms is demonstrated by measurement results

Adaptive Filtering with Bandwidth Constraints in the Feedback Path

Abstract This paper introduces a new, adaptive-filter-based controller that shows advantageous properties from the viewpoint of its communication requirement. The algorithm is called signed-error filtered-x LMS (SE-FxLMS). Its novelty is characterized by the fact that it makes possible data compression in the feedback path of adaptive-filter-based control loops in a very simple way. This feature is especially useful in such closed-loop systems where the feedback signals are transmitted over a low-bandwidth communication channel. This is a typical case in so-called networked control systems (NCS) where the communication is carried out over a shared communication channel, e.g., using a wireless sensor network. The paper introduces an analysis of the algorithm as well

Az ACH-05 hibrid-analóg számítógép és az ACH-05/TPA/i hibrid számítórendszer

A BME Műszer és Méréstechnika Tanszékén végzett több éves kutató-fejlesztő munka, a hibrid számítógép rendszer építésének befejezése alkalmával kiadott közlemény, a rendszer hardware és software elemeinek leírását tartalmazza