scholarly journals A digital phase corrector with a duty cycle detector and transmitter for a Quad Data Rate I/O scheme

2010 ◽  
Vol 7 (3) ◽  
pp. 146-152 ◽  
Author(s):  
Young-Chan Jang
2021 ◽  
Author(s):  
Hajer Tounsi ◽  
Norhane Benkahla ◽  
Ye-Qiong Song ◽  
Mounir Frikha

Abstract Long Range Wide Area Network (LoRaWAN) enables flexible long-range communication with low power consumption which is suitable for IoT applications. LoRaWAN’s performance is due on the one hand to its spreading factor modulation allowing the spread out of communication between end-devices and gateways on different frequency channels and data rates. And on the other hand, to the ability to manage for each node its data rate and its transmission power thanks to the adaptive data rate (ADR) scheme in order to increase the overall network capacity and to maximize the battery life of end devices. However, because of the Aloha access technique adopted by LoRaWAN, the risk of using the same data rate on the same channel is not negligible. Despite the limitation of the duty cycle for each node, the risk of collision is high with the increase of the number of end devices which degrades the LoRaWAN’s performance. In this context, our paper proposes different approaches to improve the performance of LoRaWAN. The first contribution consists in improving the ADR technique to meet the characteristics of a mobile environment. The new mechanism proposed, called VHMM-based E-ADR, consists of adapting the data rate of the end-device according to its position. The second contribution consists in better managing the use of the duty cycle by proposing a dynamic sharing mechanism (Dynamic Duty-Cycle). The last contribution consists in proposing a deterministic access technique to replace Aloha. Our experimental study has shown that our proposals give better results in terms of Packet Delivery Ratio (PDR) and energy consumption than basic LoRaWAN in a mobile environment.


Author(s):  
David W. Piston ◽  
Brian D. Bennett ◽  
Robert G. Summers

Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10-5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.


1978 ◽  
Vol 21 (2) ◽  
pp. 295-308
Author(s):  
Terry L. Wiley ◽  
Raymond S. Karlovich

Contralateral acoustic-reflex measurements were taken for 10 normal-hearing subjects using a pulsed broadband noise as the reflex-activating signal. Acoustic impedance was measured at selected times during the on (response maximum) and off (response minimum) portions of the pulsed activator over a 2-min interval as a function of activator period and duty cycle. Major findings were that response maxima increased as a function of time for longer duty cycles and that response minima increased as a function of time for all duty cycles. It is hypothesized that these findings are attributable to the recovery characteristics of the stapedius muscle. An explanation of portions of the results from previous temporary threshold shift experiments on the basis of acoustic-reflex dynamics is proposed.


2017 ◽  
Vol 5 (3) ◽  
pp. 713
Author(s):  
Mukhlis '

Based on the observation of some teachers found the symptoms as follows: the lack of abilityof Indonesian teachers in designing learning program (RPP), the learning device is only usedas a supplement and not to the needs of teaching, most teachers again if asked the lessonanswered not have or has not been made. The purpose of this research is to improve theability of Indonesian teachers in designing learning program (RPP) at SDN 015 PagaranTapah Darussalam through the method of administration tasks. This type of research is actionresearch school. Subjects in this study were teachers Indonesian as many as 12 people. Basedon the analysis and discussion can be concluded that the method of administration tasks canimprove the ability of Indonesian teachers in making learning device in SDN 015 PagaranTapah Darussalam through the method of administration tasks. Under these conditions, thelevel of acceptance of teachers increased. The aspect ratio capability Indonesian teachers inpreparing lesson plans through the provision of duty cycle I and II of the increase from 56%and the second cycle to 79%.


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