Papers by Keyword: Modulation

Abstract: The amount of energy generated by an Organic Photovoltaic (OPV) system depends mainly on the following.Such as solar temperatures and irradiations. Depending on the high cost and low efficiency of an organic photovoltaic system, it can be operated at the maximum power point (MPPT) that changes with solar radiation, temperature or load variations. This work presents an improved algorithm for tracking the maximum power point (MPPT) of a OPV system under real climatic conditions. The proposed MPPT is based on the perturbation and observation (P&O) strategy and the variable pitch method which controls the load voltage to ensure optimum operating points of a OPV system.

Abstract: The essence of my paper is to intricately look at data transfer with various modulation techniques over various communication channels. And run simulations to uncover the Bit Error Rate (BER) of various relevant scenarios. I will evaluate the performance of modulation techniques from Binary Phase Shift Keying (BPSK or 2PSK) to 16PSK and other modulation techniques with the consideration of time. Their performance will be evaluated and analyzed by calculating their probability of bit error rate (BER) versus the Energy per bit to spectral noise density (Eb/No) over various wireless channel models such as the Additive White Gaussian Noise (AWGN), Rayleigh channel and Ricean channel. My simulation results will graphically display the effective performance of each communication scenario; it will give us a better understanding of why performances of data communications techniques.

Abstract: Dust-removing blower is a key equipment in sintering plants, which can provide enough wind and negative pressure. It can also improve the efficiency of dust-removing. The vibration level of a dust-removing blower in a sintering plant is very high, which is beyond its normal value. Due to the complex working condition and strong background noise, it is difficult to extract fault features from the vibration signal of the dust-removing blower. Therefore, fault analysis of the blower is very difficult. Since the modulation phenomenon existed in the vibration signal of the blower is found, the envelope analysis based on the Hilbert transform is proposed to demodulate the vibration signal. The frequency spectrum of the demodulated signal shows that the first order frequency characteristic is obvious, which can effectively reveal the dynamic unbalance of the rotor system is the main reason of the abnormal vibration of the blower. According to this diagnosis, some possible reasons for the unbalance are proposed, as well as advices regarding to the repair of the blower system. Moreover, the test and analysis are conducted on the repaired blower system. The results show that the unbalance problem is eliminated and the blower can work normally, which can validate the accuracy and reliability of the proposed diagnosis method for fault analysis of the dust-removing blower.Keywords: dynamic unbalance; modulation; dust-removing blower; Hilbert Transform

Abstract: The intermediated strain can convert a magnetic field to an electric output signal in a magnetostrictive-piezoelectric layered composite via three parameters: the magnetoelastic coupling, the piezoelastic coupling and the mechanical impedance. These three parameters are dominated respectively by the magnetostrictive coefficient, the piezoelectric coefficient and the mean flexibility of material in the composite. Focusing on these three parameters, many investigations on the ME enhancement have been carried out by choosing the correct material or by adjusting the ratio between the two phases in the composite [4]. Thereafter, the noise performance of ME laminates has been studied for applications as a magnetic sensor. In the last several years, the intrinsic noise sources for both the composite and the amplifier circuit have been mathematically modeled and experimentally characterized. The passively sensed signal can be amplified by either a voltage or a charge method. Furthermore, the noise contributions from the detection electronics were also integrated in the noise performance analysis [5]. According to these studies, dielectric dissipation in the piezoelectric phase is the main contribution to the noise floor for low-frequency magnetic field sensing even though the equivalent current noise source from the electronics induce fluctuations in the output signal of the low-frequency charge detection as well [6].

Abstract: High-frequency electronic circuit is an important basic specialized course for the major of electronic information engineering, communication engineering, and electronic science and technology. Combined with a dozen years of classroom teaching experience and started from several aspects like relevancy of front-back courses, teaching framework and theoretical teaching content, this paper will discuss analogy teaching method of related content about signal amplifier, mixing, modulation and demodulation in order to help students to understand chapter structure. In the process of teaching, we should pay more attention to students ' weaknesses of knowledge, then stimulate their interests in learning and improve the teaching effectively quality.

Abstract: In order to improve the network throughput and anti-jamming capability of UAV communications, physical layer network coding is applied in the UAV communications. Simulation results show that: the use of physical layer network coding can not only improve network throughput greatly, reduce the error rate of communication, but also enhance its anti-jamming capability,which satisfy UAVs’ requirements in modern warfare.

Abstract: This paper presents the systematic evaluation of performance of indoor optical wireless communication using different modulation schemes and micro electro mechanical systems - single channel imaging receiver (MEMS-SCIR). For the future modern world, indoor optical wireless communications (OWC) play a vital role. The main objective is to compare the performance of various modulation schemes in terms of their bit error probability. On -off keying (OOK) and pulse position modulation (PPM) are widely used in optical wireless communication for its simplicity. Here different digital modulation schemes are approached; bit error rate (BER) is calculated over additive white Gaussian noise channel (AWGN). M-quadrature amplitude modulation (MQAM) gives a better BER performance compared to the M- phase shift keying (MPSK). Thus, MQAM based MEMS-SCIR provides better performance in indoor optical wireless communications.

Abstract: Multi-phase Interpolation Filters are used widely in wireless communication. Based on the requirements of a high data rate satellite modem, this paper analyses the basic design principle of a multi-phase interpolation filter. A new design scheme of multi-phase interpolation filter is presented and implemented with VHDL TOP-DOWN method on FPGA. Finally, part simulation and application test results are given.

Abstract: The main research content of this article is to design a direct sequence spread spectrum communication system based on software radio technology. In this paper, design of spread spectrum receiver system directly to intermediate frequency sampling signal processing, after internal processing directly output transmission baseband signal information.

Abstract: The equivalent magnetic noise of the magnetoelectric (ME) layered composite sensors has been investigated for various modulation techniques. The ME thin film response to an electric modulation or a magnetic modulation can be sensed by using either a charge amplifier or a coil wound around the sample and then demodulated by a synchronous detector. The equivalent magnetic noise for these excitations methods has been compared. As expected, the low-frequency fluctuations can be lowered when the magnetoelectric sensor is operated in a modulation mode. Results show that these methods can give the same level of equivalent magnetic noise for a certain strain-excitation. In theory, mechanical noise appears as the only dominant noise source after the demodulation process in the case of a certain strong amplitude excitation carrier signal. By using these modulation techniques, an equivalent magnetic noise level of 10-100 pT/Hz at 1 Hz was achieved with DC capability.