Application of Low-Frequency Communication System in Smart Plug Based on AVR MCU

2010 ◽  
Author(s):  
Zhao Honglin ◽  
Zhang Peng ◽  
Xing Tongchao ◽  
Yang Zhaofeng
Keyword(s):  
Communication System ◽  
Low Frequency ◽  
Avr Mcu

scholarly journals A Design of Dual Broadband Antenna in Mobile Communication System

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Jianming Zhou
Keyword(s):  
Mobile Communication ◽  
Communication System ◽  
High Frequency ◽  
Microstrip Line ◽  
Low Frequency ◽  
Dielectric Substrate ◽  
Frequency Bandwidth ◽  
Broadband Antenna ◽  
Feeding Method ◽  
Frequency Unit

A design of dual broadband antenna is proposed in this paper; it consists of one low frequency unit and two high frequency units. The low frequency unit consists of a pair of printing vibrators; the high frequency unit consists of a pair of printing oscillators, which is bent at its end, and high frequency unit and low frequency unit are set on the same dielectric substrate. Through adding a parasitic unit on antenna, it can enhance frequency bandwidth without affecting the bandwidth. In the high frequency unit, it adopts gap-coupled microstrip line feeding method in order to get enough bandwidth. Through the test of dual broadband antenna, it can be found that, in the low frequency part, the antenna covers 20% bandwidth of the total bandwidth, and it covers the frequency from 800 MHz to 980 MHz. In the high frequency, the antenna covers 60% of total bandwidth and its frequency is from 1540 MHz to 2860 MHz, so the designed antenna can satisfy the frequency requirements of 2G/3G/LTE (4G) communication system.

scholarly journals Development of an Efficient Indoor Optical System using Different Wavelet Transforms

2021 ◽  
Author(s):  
Ankita Aggarwal ◽  
Gurmeet Kaur
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Communication System ◽  
Wavelet Transforms ◽  
Low Frequency ◽  
Digital Signal ◽  
Fluorescent Light ◽  
Discrete Wavelet ◽  
Stationary Wavelet Transform ◽  
Light Interference

For an effective communication system whether indoor or outdoor, the most important concern is minimum noise. In this paper, an efficient noise reduction technique is presented using various wavelet transform techniques for indoor optical wireless communication system (IOWC). In IOWC system, Fluorescent Light Interference (FLI) is main source of noise. Here, in this paper three methods are used to reduce the effect of noise from a digital signal. These are Discrete Wavelet Transform (DWT), Stationary Wavelet transform (SWT) and Discrete Wavelet transform-Stationary Wavelet Transform (DWT-SWT). Through sub band coding in DWT the signal is decomposed into lower sub bands of high and low frequency respectively of unequal size; while in SWT the decomposed signal have sub bands of equal size. In DWT-SWT the high frequency components of both DWT and SWT are added. Using Pulse Position Modulation, the comparison between these three techniques is described here to enhance the overall performance of the IOWC system.

scholarly journals An Improved Design and Implementation of a Range-Controlled Communication System for Mobile Phones

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4997
Author(s):  
Mingyang Gong ◽  
Haichun Zhang ◽  
Zhenglin Liu
Keyword(s):  
Communication System ◽  
Near Field ◽  
Low Frequency ◽  
Cmos Technology ◽  
Clock Recovery ◽  
Current Consumption ◽  
System Clock ◽  
Communication Distance ◽  
Communication System Design ◽  
Improved Design

The Short-range-controlled communication system (RCC) based on a subscriber identity module (SIM) card is a replacement for the standard near-field communication (NFC) system to support near-field payment applications. The RCC uses both the low-frequency (LF) and high-frequency (HF) wireless communication system. The RCC communication distance is controlled under 10 cm. However, current RCCs suffer from compatibility issues, and the LF communication distance is lower than 0.5 cm in some phones with completely metallic shells. In this paper, we propose an improved LF communication system design, including an LF transmitter circuit, LF receiver chip, and LF-HF communication protocol. The LF receiver chip has a rail-to-rail amplifier and a self-correcting clock recovery differential Manchester decoder, which do not have the limitations of accurate gain and high system clock. The LF receiver chip is fabricated in a 0.18 μm CMOS technology platform, with a die size of 1.05 mm × 0.9 mm and current consumption of 41 μA. The experiments show that the improved RCC has better compatibility, and the communication distance reaches to 4.2 cm in phones with completely metallic shells.

Numerical Simulation and Experimental Research of Hydrophone Flow Noise

2020 ◽  
Author(s):  
Mingyuan Li ◽  
Jianzhang Liu ◽  
Yan Wei ◽  
Fengzhong Qu ◽  
Minhao Zhang ◽  
...  
Keyword(s):  
Flow Field ◽  
Acoustic Communication ◽  
Communication System ◽  
Signal To Noise Ratio ◽  
Low Frequency ◽  
Sound Field ◽  
Underwater Acoustic Communication ◽  
Acoustic Analogy ◽  
Underwater Acoustic ◽  
Flow Noise

Abstract Underwater acoustic communication is an important technology in deep-sea research. In underwater acoustic communication system, when hydrophone as acoustic receiver is exposed to sea environment and moves along with an underwater vehicle, its performance is prone to be affected by various ambient noises, among which its generated flow noise is the major source. This would especially influence the performance and shorten the communication distance of underwater acoustic communication system. In this paper, we try to unveil how the flow field is correlated with the flow noise of hydrophone. The Large Eddy Simulation (LES) method and acoustic analogy were used to simulate the flow field and the sound field around hydrophone, respectively. The flow noise of hydrophone at different moving velocities was obtained. Then experiments in an anechoic tank were carried out to verify the simulation results. The subsequent analysis of the experimental results shows that the flow noise has obvious influence on underwater communication, and as the hydrophone moves faster, its sound pressure level climbs up higher. This study also further verifies the reliability of simulating the flow noise of bare hydrophone by computational fluid dynamics, and provides the theoretical basis for improving the signal-to-noise ratio of low-frequency underwater acoustic communication system.

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