Search results for "Keying"
showing 10 items of 37 documents
Oil filled MV/LV Power Transformer Behavior in Narrow Band Power Line Communication Systems
2012
The aim of this paper is to characterize oil-filled power transformers in the narrow-band power-line communication (PLC) frequency range of 50-150 kHz. A new model is proposed for such type of a transformer, in the aforementioned frequency range of interest, in order to study its influence on the signal transmission and to investigate the possibility that the PLC signal can cross the power transformer itself. The new model is simpler than those previously proposed in literature, and it can be used in the whole frequency range available for NB PLC according to the CENELEC EN 50065-1 A-band. In order to validate the model, simulation and measurement results are compared for four oil-filled po…
An FPGA-Based Software Defined Radio Platform for the 2.4GHz ISM Band
2006
A prototype of a Software Defined Radio (SDR) platform has been successfully designed and tested implementing a reconfigurable IEEE 802.11 and ZigBee receiver. The system exploits the reconfiguration capability of an FPGA for implementing a number of receiver configurations that share the same RF front-end. Configurations can be switched at run time, or can share the available logic and radio resource.
Experimental Demonstration of 50-Mb/s Visible Light Communications Using 4<inline-formula> <tex-math notation="TeX">$\,\times\,$ </tex…
2014
This letter reports the experimental demonstration of an indoor visible light nonimaging multiple-input multiple-output system with an aggregate error free bit rate of 50 Mb/s over a distance of 2 m. The system uses four independent white LED transmitters, each transmitting 12.5 Mb/s of data in the ON-OFF keying nonreturn zero format, and four independent nonimaging optical receivers. The performance of four detection methods ranging from the basic channel inversion to the more advanced space time techniques is compared experimentally. The results gathered demonstrate that the simplest technique is capable of the same bit error rate as the most complex scheme. The system also provides full …
Narrowband power line communications for medium voltage smart grids
2014
The aim of the paper is to show how narrowband power line communications (NB-PLCs) can be a valid solution for medium voltage grids. Advantages and drawbacks of this solution are analyzed, starting from some experimental communication results, which were carried out on the medium power system networks of the islands of Ustica and Favignana, in the presence of the net voltage. Furthermore, some communication architectures and hardware prototypes based on NB-PLCs are proposed for different smart grids applications.
Development of a Coupling System for Medium Voltage Power Line Communication in the CENELEC A Frequency Band
2016
In this paper the performances of a new power line communication (PLC) coupling system for medium voltage (MV) smart grids are investigated in the CENELEC A frequency band (i.e. 3 - 95 kHz). The new coupling solution is based on the use of the capacitive divider of the voltage detecting system (VDS) as PLC coupler to the MV network. According to IEC 61243-5, VDS are worldwide used to reveal the presence of the mains voltage to ensure the safety of the operators. A proper interface circuit has been invented and patented to couple the PLC signal through the VDS. In this way no dedicated MV PLC coupler is required, thus avoiding the related costs of the coupler, of its installation, and those …
Ethernet FSO Communications Link Performance Study Under a Controlled Fog Environment
2012
In this letter the performance of a free space optical (FSO) communication link in the presence of fog is experimentally investigated in an indoor environment. A dedicated indoor atmospheric chamber, replicating the outdoor environment, is being used to evaluate the FSO link performance under the fog condition. Theoretical analysis supported by the experimental evaluation has been carried out for the intensity modulation/direct detection on-off keying non-return-to-zero (OOK-NRZ), OOK return-to-zero (OOK-RZ) and four pulse position modulation (4-PPM) modulation formats at the Ethernet baseline data-rate. The results shown indicate that the 4-PPM signalling scheme is the most robust to the f…
A simple joint estimation-detection technique for OFDM systems
2005
In this work a simple approach for the joint estimation-detection in a frequency selective severe fading environment of OFDM signals adopting PSK constellations is presented. A linear predictor of suitable order is adopted for the channel estimation in the frequency domain. The predictor coefficients are estimated on the basis of a sample estimation of the autocorrelation of the channel frequency response, aided by a preliminary differential decoding, in a blockwise manner. The detection technique proposed here is based on a simple tree search where a small number of best survivor paths are maintained at each step. Despite the simplicity of above detection approach, the simulation results s…
Optimum pulse shape for minimum spectral occupancy in FSK signals
1984
The characteristics of a frequency shift keying (FSK) signal giving rise to maximum power within a prescribed frequency band are determined. The baseband pulse shape extends over any integer number of bit periods. An integral equation for the optimum pulse shape is derived and some simple properties of the solution are investigated. The equation has been solved for some values of the product of the prescribed band times the pulse duration and the signal shape is shown. Our results for the particular case of pulses only one bit period long are presented for purpose of comparison with results known in the literature. Plots of out-of-band power for some values of the prescribed band and of pul…
Design and Characterization of a New MV PLC Coupler for Smart Electric Energy Systems
2018
This paper deals with the design, modeling and characterization of a new coupling system for medium voltage (MV) narrow band power line communications (NB-PLC). It exploits the capacitive divider of voltage detecting systems (VDSs) normally used to reveal the mains voltage presence, thus avoiding the use of dedicated MV couplers. The proposed coupling system was patented by the authors. In this paper, the modeling of the VDS capacitive divider is presented, using a proper characterization method. Moreover, the interface card design is described, based on simulation of the whole PLC transmission channel. Laboratory tests are also presented and discussed. More in detail, a frequency response …
On the error sequences of M-ary FSK modulation schemes over Nakagami-m fading channels
2012
In this paper, we have studied some important statistical properties of error sequences of M-ary orthogonal frequency-shift keying (FSK) modulation schemes over Nakagami-m fading channels. We have derived the joint probability density function (PDF) of error sequences of arbitrary length. From the joint PDF, we have found an analytical solution for the autocorrelation function (ACF) of the error sequences. The correctness of the analytical expression for the ACF of error sequences has been confirmed by simulations, where the simulation results are obtained by using the sum-of-sinusoids principle. The derived joint PDF of error sequences is useful for the development of first-order and highe…