The instantaneous power-line frequency synchronized superimposed chart was proposed by the authors to visualize the effects of an AC adapter for PLC (Power Line Communications) transmission. In order to most properly draw the superimposed chart, it is requisite to synchronize data packets and instantaneous power-line frequency data, which are asynchronously captured by separate PCs (Personal Computers). This paper proposes a synchronization algorithm for these data, and shows the effectiveness of the proposed algorithm. Furthermore, an algorithm to compensate the fixed frequency measurement error made by a digital multi-meter is proposed. Finally, it is shown that the communications forbidden time, the duration when PLC burst signals are not correctly received due to the effects of the AC adapter, is properly shown by adopting the proposed two algorithms as well as how burst signals containing different number of data packets are transmitted in the moments other than the communications forbidden time.
Networked control systems (NCSs) using the Internet will soon become widespread. In NCSs, time delays and information losses cause system performance degradation and destabilization. It is known that a communication disturbance observer (CDOB)-based compensator can estimate and suppress the effect of time delays on the system as a network disturbance. We applied a CDOB-based compensator to NCSs with not only time delays but also information losses and theoretically analyzed the information-loss compensation scheme. However, the performance of the CDOB-based compensator for only information losses in real NCSs has not been experimentally evaluated. This letter demonstrates an information-loss compensation scheme using a CDOB for NCSs. Experiments using a networked motion control system show that the CDOB-based compensator can estimate and suppress the effect of information losses on an NCS.
Bi-space shift keying (BiSSK) can increase the spectral efficiency of space shift keying (SSK) but requiring a large number of available transmit antennas. A new SSK-based modulation scheme is proposed which requires a smaller number of transmit antennas than what required in BiSSK to deliver the same transmission rate at a negligible performance loss. The proposed scheme is obtained by multiplexing two in-phase and quadrature generalized SSK (GSSK) streams and optimizing the carrier signals transmitted by the activated antennas. Performance of the proposed scheme is compared with other SSK-based schemes via minimum Euclidean distance analysis and computer simulation.
This paper presents the system concept, transceiver architecture, and control sequence for a millimeter-wave (60-GHz) band close proximity high-speed data transfer system. The communication range and the use case are limited to achieve fast link setup time and a stable point-to-point connection. Prototype equipment developed for the system includes three types of wireless transceivers; cooperative operation among them makes it possible to reduce the link setup time and limit the communication range. The system’s control sequence enables the link setup time to be reduced from 7 seconds to 0.2 seconds.