Characterization of Signal Propagation through Limb Joints for Intrabody Communication

2011 ◽  
Vol 1 (2) ◽  
pp. 1-12 ◽  
Author(s):  
MirHojjat Seyedi ◽  
Zibo Cai ◽  
Daniel T. H. Lai
Keyword(s):  
Data Transmission ◽  
Empirical Studies ◽  
Low Frequency ◽  
Signal Propagation ◽  
Propagation Path ◽  
Signal Attenuation ◽  
Frequency Bands ◽  
Physical Layers ◽  
Signal Propagation Path

Intrabody communication (IBC) is one of the recent physical layers of the IEEE 802.15.6 Wireless Body Area Networks (WBAN) communication standard. It is employed for data transmission in low frequency bands (21 MHz as per standard, 0.3-120 MHz in literature), providing up to 10 Mbps data throughput. An effective way to increase data rate communication is to determine higher operation frequency bands. This paper reports empirical studies which explore signal propagation through the human body including limb joints within the 0.3-200 MHz frequency range. Results show that minimum signal attenuation points occur at 50 MHz and 150 MHz within the range of investigation. The presence of the joint segments along the signal propagation path causes on average 2.0 dB loss (at 50 MHz and 150 MHz), 6.0 dB loss (<1 MHz) and less than 3.0 dB (>150 MHz) compared to limb segments.

scholarly journals DPFFs:C2MOSDirect Path Flip-Flops for Process-Resilient Ultradynamic Voltage Scaling

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Myeong-Eun Hwang ◽  
Sungoh Kwon
Keyword(s):  
Load Condition ◽  
Signal Propagation ◽  
Propagation Delay ◽  
Propagation Path ◽  
Direct Connection ◽  
Standard Cell ◽  
Direct Path ◽  
Output Load ◽  
Adaptive Body Bias ◽  
Signal Propagation Path

We propose two master-slave flip-flops (FFs) that utilize the clocked CMOS (C2MOS) technique with an internal direct connection along the main signal propagation path between the master and slave latches and adopt an adaptive body bias technique to improve circuit robustness.C2MOSstructure improves the setup margin and robustness while providing full compatibility with the standard cell characterization flow. Further, the direct path shortens the logic depth and thus speeds up signal propagation, which can be optimized for less power and smaller area. Measurements from test circuits fabricated in 130 nm technology show that the proposed FF operates down to 60 mV, consuming 24.7 pW while improving the propagation delay, dynamic power, and leakage by 22%, 9%, and 13%, respectively, compared with conventional FFs at the iso-output-load condition. The proposed FFs are integrated into an8×8FIR filter which successfully operates all the way down to 85 mV.

scholarly journals DIFFICULTIES ASSOCIATED TO THE ULTRASONIC IMAGING OF SMALL SCALE MODELS OF STRATIGRAPHIC DEPOSITS

2013 ◽  
Vol 31 (4) ◽  
pp. 673
Author(s):  
Cássio Stein Moura ◽  
Roseane Marchezi Misságia ◽  
Marco Antonio Rodrigues Ceia
Keyword(s):  
Rayleigh Scattering ◽  
Low Frequency ◽  
Small Scale ◽  
Turbidity Currents ◽  
Signal Attenuation ◽  
Large Signal ◽  
Sediment Grain Size ◽  
Mechanical Waves ◽  
Scale Models

ABSTRACT. Mechanical waves are commonly used on the characterization of geological systems. Highly compacted real systems require low frequency waves on the order of tens of hertz. Tabletop models span the millimetric scale and therefore need higher frequency waves ranging up to the ultrasound band. We have used an ultrasonic seismic equipment to image tabletop geological systems. The seismograms enabled the identification of some features under investigation but were limited to discern some objects of interest, such as, the interface between a coal layer on top of a sand layer. We believe that the low consolidation of the material has intensified the Rayleigh scattering of the incident wave leading to a large signal attenuation and to the difficulty on layer discrimination. We propose some ways to circumvent such a problem including increasing the material consolidation or the sediment grain size in order to reduce the scattering effects.Keywords: mechanical waves, deposit imaging, stratigraphy, turbidity currents. RESUMO. A utilização de ondas mecânicas é uma opção recorrente na caracterização de sistemas geológicos. Sistemas reais de alta compactação costumam ser analisados por ondas mecânicas com frequências da ordem de dezenas de hertz. Modelos de bancada requerem o uso de frequências mais altas, na faixa do ultrassom, para possibilitar a definição de detalhes milimétricos. Utilizamos um sistema de levantamento sísmico ultrassonográfico para visualizar modelos geológicos de bancada. Os sismogramas produzidos identificaram algumas feições sob investigação, mas apresentaram limitações na discriminação dos objetos de interesse, a saber, a interface entre uma camada de carvão sobre uma camada de areia. Acreditamos que a baixa consolidação domaterial tenha intensificado o espalhamento Rayleigh da onda incidente levando a uma grande atenuação do sinal de retorno e à consequente dificuldade em discriminar as camadas. Propomos algumas formas de diminuir esse problema que incluem o aumento da consolidação do material ou do tamanho de grão dos sedimentos para reduzir os efeitos de espalhamento.Palavras-chave: ondas mecânicas, visualização de depósitos, estratigrafia, correntes de turbidez.

Investigations of the lower ionosphere over Antarctica via ELF-VLF radiowaves

1993 ◽  
Vol 5 (1) ◽  
pp. 107-113 ◽  
Author(s):  
A. E. Reznikov ◽  
A. I. Sukhorukov ◽  
D. E. Edemskii ◽  
V. V. Kopeikin ◽  
P. A. Morozov ◽  
...  
Keyword(s):  
Near Field ◽  
Lower Ionosphere ◽  
Signal Propagation ◽  
Propagation Path ◽  
New Methods ◽  
The Earth ◽  
Resonance Band ◽  
Cavity Resonances ◽  
Lightning Discharges ◽  
Signal Propagation Path

The paper discusses ELF-VLF investigations of the low Antarctic ionosphere. Two new methods of lower ionospheric diagnostics are based on an investigation of the VLF electromagnetic field structure in the Earth-ionosphere cavity. One method deals with the analysis of local transverse cavity resonances in the near field of an emitter (a horizontal antenna) with a frequency (~1.5-8 kHz) in the range of the first few resonances. The other method, based on tweek investigations, is applicable under night conditions and enables the characteristics of the low ionosphere to be determined over a signal propagation path. The use of the ELF-VLF transmitter at Siple Station provides a unique opportunity to implement these methods, as does the ELF multipoint recording in the Schumann resonance band of atmospherics excited by powerful lightning discharges.

scholarly journals Variation of Low-Frequency Time-Code Signal Field Strength during the Annular Solar Eclipse on 21 June 2020: Observation and Analysis

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1216
Author(s):  
Xin Wang ◽  
Bo Li ◽  
Fan Zhao ◽  
Xinyu Luo ◽  
Luxi Huang ◽  
...  
Keyword(s):  
Field Strength ◽  
Solar Eclipse ◽  
Low Frequency ◽  
Signal Propagation ◽  
Normal Operation ◽  
Time Code ◽  
Long Distance ◽  
Time Service ◽  
Annular Solar Eclipse ◽  
Signal Field

Due to the occlusion of the moon, an annular solar eclipse will have an effect on the ionosphere above the earth. The change of the ionosphere, for the low-frequency time-code signal that relies on it as a reflection medium for long-distance propagation, the signal field strength, and other parameters will also produce corresponding changes, which will affect the normal operation of the low-frequency time-code time service system. This paper selects the solar eclipse that occurred in China on 21 June 2020, and uses the existing measurement equipment to carry out experimental research on the low-frequency time-code signal. We measured and analyzed the signal field strength from 20 June 2020 to 23 June 2020, and combined solar activity data, ionospheric data, and geomagnetic data, and attempted to explore the reasons and rules of the change of signal parameters. The results showed that the field strength of the low-frequency time-code signal changed dramatically within a short time period, the max growth value can reach up to 17 dBμV/m and the variation trend yielded ‘three mutations’. This change in signal field strength is probably due to the occurrence of a solar eclipse that has an effect on the ionosphere. When the signal propagation conditions change, the signal strength will also change accordingly.

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