Applied Mechanics and Materials Vols. 602-605

Abstract: A compact LTCC filter using LC resonators is presented. The resonator is made up of the multilayer capacitors and inductors, which are printed on multilayer ceramic. Four resonators are exploited, which makes the filter have wide passband. By properly controlling the coupling elements of each resonator, two transmission zeros can be located at both sides of the passband for better selectivity. Measured results show a bandwidth of more than 47.2%, where the centre frequency is 1.25GHz. The whole size of the filter is 4.5×3.2×1.7mm³.

Abstract: For the contradiction between convergence rate and convergence precision in the CMA blind equalization with the fixed momentum factor, a variable momentum CMA blind equalization is proposed The output error power of the blind equalizer is acted as the parameter, which control the adjustment of the momentum factor adaptively based on nonlinear transformation function. The algorithm can obtain faster convergence rate and higher convergence precision, also the performance of the blind equalization is improved. The simulation results show that, compared with the CMA blind equalization with the fixed momentum factor, CMA blind equalization with variable momentum based on nonlinear transform can obtain better performance

Abstract: According to the requirement of the vehicle-mounted radar and taking into consideration of main circuit, amplifying circuit, waveform conversion circuit, automatic gain circuit and voltage control circuit, and other factors of the AT-cut quartz crystal resonator. We designed a small single layer constant temperature high stability crystal vibration for vehicle-mounted radar.

Abstract: . The diaphragm capsule, one of the most important components of the vacuum pressure sensor, should have linear elastic characteristic. Make research on simulation of the diaphragm capsule packaged in vacuum pressure sensor by finite elements Analysis to obtain its elastic characteristic, and get its elastic characteristic by experiment. Compare the displacements between simulation and experiment at each load, the maximum error is smaller than 5%. The analysis results can be used for the structure design of the diaphragm capsule.

Abstract: A digital storage oscilloscope module in automatic test equipment was designed based on PIX bus. The field programmable gate array (FPGA) is used as the logic control unit. The circuit of high speed ADC and FPGA interface, clock management, and high speed data access were designed based on hardware modules. The digital storage oscilloscope module was successfully applied to the practical test system, whose performance was good, stable, and achieved the desired design goals.

Abstract: The absorption coefficient spectra and refractive index spectra of food grade, industrial grade and pharmaceutical grade paraffin wax, the three different types of paraffin wax within the terahertz frequency range from 0.2 to 2.2 THz are measured using transmission-type terahertz time-domain spectroscopy. The average refractive indexes of food grade, industrial grade and pharmaceutical grade paraffin wax in the frequency range are respectively 1.50, 1.49 and1.46. The three different types of paraffin wax all have weak absorption for terahertz waves and each paraffin wax have several obvious absorption peaks. However, all found absorption peak positions of the three different types of paraffin wax are so close that the three are relatively difficult to be identified using transmission-type terahertz technique in present experimental conditions.

Abstract: The special driver for tunable F-P filter is expensive, so it has an important application value to design a driver with stable performance and low cost. In this paper, the field programmable gate array (FPGA) was chosen as the core chip to constitute triangular signal generator based on direct digital frequency synthesizer (DDS). The output frequency of waveform ROM look-up table will be altered by changing frequency control word. Then, the products of amplitude word and signals of ROM table output were transmitted to DAC to be converted into analog signal. The variable frequency and amplitude modulation signals were got after smoothed by low pass filter. The frequency range of driving signal is 1 Hz~10 KHz, and the resolution of frequency is 0.1 Hz. The amplitude range is 1 V~10 V, and the resolution of amplitude is 0.1 V. The simulation and experimental results show that the driver has the characteristics of simple structure, stable signal, adjustable frequency and amplitude and lower cost. It can satisfy the requirements of tunable F-P filter driven in practical engineering.

Abstract: A new class of three-dimensional chaotic system is constructed by algebraic methods, which has a similar structure with the classic Lorenz system but contains the square term. The equilibrium point of the system stability is analyzed, and the numerical simulation is carried on the bifurcation diagram and Lyapunov exponent. The chaotic circuit of these systems is designed by using the software of EWB. The results of the experimental simulation verify the existence of the chaotic attractor, which provides theoretical reference to the application of such system.

Abstract: According to the difficulties in charging large current problems for lead battery, a charging method based on the energy library was proposed in this paper. The energy library was composed by ultracapacitors as charging power supply.This method can greatly shorten the charging time, improve the efficiency of charge.

Abstract: A large number of constant power loads (CPLs) are included in the integrated power system (IPS). This paper firstly studied the characteristics of the load, based on which concluded the physical mechanism of static instability and the chief factors of the static stability of IPS.