Current Issue : July-September Volume : 2023 Issue Number : 3 Articles : 5 Articles
Ultrashort pulse (USP) signal with high peak power is also called ultrawideband signal, which has a broad application prospect in radar detection and electronic countermeasures and other fields. In this paper, an acquisition device is proposed to obtain the USP signal with ultrahigh compression efficiency (CE) and ultrahigh power compression gain (PCG). The long input pulse with a time length of μs level can be compressed to a narrow pulse with a pulse width of 450 ps level (2.6–3.9 GHz) by using the proposed USP acquisition device. Under the condition without loss, the CE of the USP acquisition device can reach up to 98% according to the simulated results. In the simulation, if the material of the acquisition device is set to copper material, then the CE has some reduction due to conductor loss. In order to demonstrate the effectiveness of the proposed USP acquisition device, a USP acquisition device is established and measured. According to the measurement results, a measured PCG of 27 dB is achieved and the pulse width is approximately 460 ps. The peak power of the output USP signal reaches to 100kW under the condition of input pulse with a power of 200 W....
This paper presents a new recursive trigonometric (RT) technique for Field-Programmable Gate Array (FPGA) design implementation. The traditional implementation of trigonometric functions on FPGAs requires a significant amount of data storage space to store numerous reference values in the lookup tables. Although the coordinate rotation digital computer (CORDIC) can reduce the required FPGA storage space, their implementation process can be very complex and time-consuming. The proposed RT technique aims to provide a new approach for generating trigonometric functions to improve communication accuracy and reduce response time in the FPGA. This new RT technique is based on the trigonometric transformation; the output is calculated directly from the input values, so its accuracy depends only on the accuracy of the inputs. The RT technique can prevent complex iterative calculations and reduce the computational errors caused by the scale factor K in the CORDIC. Its effectiveness in generating highly accurate cosine waveform is verified by simulation tests undertaken on an FPGA....
In this paper, a tensor-based approach to blind despreading of long-code multiuser DSSS signals is proposed. We aim to generalize the tensor-based methods originally developed for blind separation of short-code multiuser DSSS signals to long-code cases. Firstly, we model the intercepted long-code multiuser DSSS signals with an antenna-array receiver as a three-order tensor with missing values, and then, the blind separation problem can be formulated as a canonical or parallel factor (CANDECOMP/PARAFAC) decomposition problem of the missing-data tensor, which can be solved using optimum methods. Secondly, a constrained Cramér–Rao Bound (CRB) is also derived to provide a performance benchmark for the proposed approach. Simulation results verify the feasibility of our proposed approach in the case of low signal-to-noise (SNR) conditions....
Vehicular ad hoc networks (VANETs) are an eminent area of intelligent transportation systems (ITS) which includes vehicle tracking, positioning, and emergency warnings. For protective applications, vehicle localization in the urban area is a significant problem. Global Positioning Systems (GPS) are one of the many solutions that have been offered, although they do not offer accuracy. To locate a target vehicle accurately, a unique approach called received signal strength- (RSS-) based localization scheme has been proposed. By detecting signals within its range, it establishes communication through roadside units (RSUs) and determines the typical RSS. Following the discovery of the RSS, the RSS-based localization algorithm helped in determining the precise position of the vehicle. The high signal-to-noise ratio of the proposed algorithm, which is derived from neighbouring RSUs, is its key component. The vehicle’s Cramer Rao lower bound (CRLB) is examined after its position is discovered. Various experimentations considering dynamic vehicles ranging from 2 to 100, localization error, ranging error, and throughput have been conducted which demonstrates that the proposed algorithm (RSS) has better results (87%, 80%, and 120) than other well-established least squares (LS) and weighted least squares methods (WLS)....
This research work is aimed at studying different rock types and the effect of their mineral contents on an active 434MHz RFID card’s radio signal attenuation. This research was done at the ONKALO nuclear waste storage facility using radio frequency identification (RFID) equipment. First, the studied area and research plan, including the used system and equipment, are explained. After this, the researched areas of rock types and their effects on radio signals are presented. This work focused mainly on occupational safety, but it also investigated whether it would be possible to use RFID technology in producing mines as well, especially in the boundary layer of the ore body. This research can help the design of communication frequencies for autonomous devices....
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