Wenke Lu

Solving Three Key Problems of Wavelet Transform Processor Using Surface Acoustic Wave Devices

Abstract-In this paper, we present the bulk acoustic wave (BAW), the sound-electricity reclamation (SER), and the insertion loss as the three key problems of a wavelet transform processor using surface acoustic wave devices. The solutions to these problems are achieved in this study. The more the number of electrode pairs for the interdigital transducer (IDT) is, the weaker the excited BAW is, so the BAW can be eliminated when the number of electrode pairs for IDT is large enough. The substrate material of a small electromechanical coupling coefficient (ECC) k2 and the low-impedance load of IDT can eliminate SER. When the output ends of the wavelet transform processors are respectively connected to the amplifiers, their insertion losses can be compensated. X-112oY LiTaO3 (small ECC k2) is used as a substrate material to fabricate the wavelet transform processor.

Optimal Frequency Band Design Scheme of Dyadic Wavelet Processor Array Using Surface Acoustic Wave Devices

In this paper, the relationship between the center frequency and radius of bandwidth and its effect on the frequency band characteristics of dyadic wavelet processor array using surface acoustic wave (SAW) devices are studied, and an optimal frequency band design scheme is proposed. For an arbitrary scale wavelet processor, we proposed that the center frequency is defined to three times of the radius of frequency bandwidth. The frequency band design scheme ensures that the frequency band coverage factor is equal to 100% at -3 dB, which avoid the signal loss caused by the discrete frequency band and the device waste caused by the redundant frequency band. With the frequency band design scheme, an experiment of implementing a dyadic wavelet processor array using SAW devices with five scales is presented. Experimental results confirm that the frequency band coverage factor equals 100% at -3 dB without discrete and redundant frequency band.

Implementing wavelet inverse-transform processor with surface acoustic wave device

The objective of this research was to investigate the implementation schemes of the wavelet inverse-transform processor using surface acoustic wave (SAW) device, the length function of defining the electrodes, and the possibility of solving the load resistance and the internal resistance for the wavelet inverse-transform processor using SAW device. In this paper, we investigate the implementation schemes of the wavelet inverse-transform processor using SAW device. In the implementation scheme that the input interdigital transducer (IDT) and output IDT stand in a line, because the electrode-overlap envelope of the input IDT is identical with the one of the output IDT (i.e. the two transducers are identical), the product of the input IDTs frequency response and the output IDTs frequency response can be implemented, so that the wavelet inverse-transform processor can be fabricated. X-112(0)Y LiTaO(3) is used as a substrate material to fabricate the wavelet inverse-transform processor. The size of the wavelet inverse-transform processor using this implementation scheme is small, so its cost is low. First, according to the envelope function of the wavelet function, the length function of the electrodes is defined, then, the lengths of the electrodes can be calculated from the length function of the electrodes, finally, the input IDT and output IDT can be designed according to the lengths and widths for the electrodes. In this paper, we also present the load resistance and the internal resistance as the two problems of the wavelet inverse-transform processor using SAW devices. The solutions to these problems are achieved in this study. When the amplifiers are subjected to the input end and output end for the wavelet inverse-transform processor, they can eliminate the influence of the load resistance and the internal resistance on the output voltage of the wavelet inverse-transform processor using SAW device.

Solution to the influence of the MSSW propagating velocity on the bandwidths of the single-scale wavelet-transform processor using MSSW device.

The objective of this research was to investigate the possibility of solving the influence of the magnetostatic surface wave (MSSW) propagating velocity on the bandwidths of the single-scale wavelet transform processor using MSSW device. The motivation for this work was prompted by the processor that -3dB bandwidth varies as the propagating velocity of MSSW changes. In this paper, we present the influence of the magnetostatic surface wave (MSSW) propagating velocity on the bandwidths as the key problem of the single-scale wavelet transform processor using MSSW device. The solution to the problem is achieved in this study. we derived the function between the propagating velocity of MSSW and the -3dB bandwidth, so we know from the function that -3dB bandwidth of the single-scale wavelet transform processor using MSSW device varies as the propagating velocity of MSSW changes. Through adjusting the distance and orientation of the permanent magnet, we can implement the control of the MSSW propagating velocity, so that the influence of the MSSW propagating velocity on the bandwidths of the single-scale wavelet transform processor using MSSW device is solved.

A novel optimal sensitivity design scheme for yarn tension sensor using surface acoustic wave device.

In this paper, we propose a novel optimal sensitivity design scheme for the yarn tension sensor using surface acoustic wave (SAW) device. In order to obtain the best sensitivity, the regression model between the size of the SAW yarn tension sensor substrate and the sensitivity of the SAW yarn tension sensor was established using the least square method. The model was validated too. Through analyzing the correspondence between the regression function monotonicity and its partial derivative sign, the effect of the SAW yarn tension sensor substrate size on the sensitivity of the SAW yarn tension sensor was investigated. Based on the regression model, a linear programming model was established to gain the optimal sensitivity of the SAW yarn tension sensor. The linear programming result shows that the maximum sensitivity will be achieved when the SAW yarn tension sensor substrate length is equal to 15 mm and its width is equal to 3mm within a fixed interval of the substrate size. An experiment of SAW yarn tension sensor about 15 mm long and 3mm wide was presented. Experimental results show that the maximum sensitivity 1982.39 Hz/g was accomplished, which confirms that the optimal sensitivity design scheme is useful and effective.

Study of low insertion loss and miniaturization wavelet transform and inverse transform processor using SAW devices.

In this paper, we propose a low insertion loss and miniaturization wavelet transform and inverse transform processor using surface acoustic wave (SAW) devices. The new SAW wavelet transform devices (WTDs) use the structure with two electrode-widths-controlled (EWC) single phase unidirectional transducers (SPUDT-SPUDT). This structure consists of the input withdrawal weighting interdigital transducer (IDT) and the output overlap weighting IDT. Three experimental devices for different scales 2(-1), 2(-2), and 2(-3) are designed and measured. The minimum insertion loss of the three devices reaches 5.49dB, 4.81dB, and 5.38dB respectively which are lower than the early results. Both the electrode width and the number of electrode pairs are reduced, thus making the three devices much smaller than the early devices. Therefore, the method described in this paper is suitable for implementing an arbitrary multi-scale low insertion loss and miniaturization wavelet transform and inverse transform processor using SAW devices.

Research on two-port network of wavelet transform processor using surface acoustic wavelet devices and its application

&NA; The goal of this research is to study two‐port network of wavelet transform processor (WTP) using surface acoustic wave (SAW) devices and its application. The motive was prompted by the inconvenience of the long research and design cycle and the huge research funding involved with traditional method in this field, which were caused by the lack of the simulation and emulation method of WTP using SAW devices. For this reason, we introduce the two‐port network analysis tool, which has been widely used in the design and analysis of SAW devices with uniform interdigital transducers (IDTs). Because the admittance parameters calculation formula of the two‐port network can only be used for the SAW devices with uniform IDTs, this analysis tool cannot be directly applied into the design and analysis of the processor using SAW devices, whose input interdigital transducer (IDT) is apodized weighting. Therefore, in this paper, we propose the channel segmentation method, which can convert the WTP using SAW devices into parallel channels, and also provide with the calculation formula of the number of channels, the number of finger pairs and the static capacitance of an interdigital period in each parallel channel firstly. From the parameters given above, we can calculate the admittance parameters of the two port network for each channel, so that we can obtain the admittance parameter of the two‐port network of the WTP using SAW devices on the basis of the simplification rule of parallel two‐port network. Through this analysis tool, not only can we get the impulse response function of the WTP using SAW devices but we can also get the matching circuit of it. Large numbers of studies show that the parameters of the two‐port network obtained by this paper are consistent with those measured by network analyzer E5061A, and the impulse response function obtained by the two‐port network analysis tool is also consistent with that measured by network analyzer E5061A, which can meet the accuracy requirements of the analysis of the WTP using SAW devices. Therefore the two‐port network analysis tool discussed in this paper has comparatively higher theoretical and practical value. HighlightsInvestigate two‐port network of WTP using SAW devices and its application.Channel segmentation method converting the WTP into parallel channels is derived.The formula of the admittance matrix for the WTP using SAW devices is offered.

Temperature compensation of the SAW yarn tension sensor

HighlightsThe possibility of the temperature compensation for the SAW yarn tension sensor is studied.The functional relationship caused by the temperature is derived.The key problems are how to determine Symbol and Symbol. Symbol. No caption available. Symbol. No caption available. Abstract The objective of this research was to investigate the possibility of the temperature compensation for the surface acoustic wave (SAW) yarn tension sensor. The motivation for this work was prompted by the oscillation frequency of the SAW yarn tension sensor varying with the temperature. In this paper, we deduce the functional relationship between the temperature variation and the oscillation frequency shift caused by the temperature. This functional relationship and the temperature sensor are used to get the oscillation frequency shift caused by the temperature, so that we can use the oscillation frequency shift caused by the temperature to implement the temperature compensation of the SAW yarn tension sensor. In this paper, we also get the relative error of the temperature compensation. The theoretical and experimental results confirm that this temperature compensation method can implement the temperature compensation of the SAW yarn tension sensor.

Study of SAW Based on a Micro Force Sensor in Wireless Sensor Network

Wireless sensor network (WSN) technology has increasingly assumed an active role in detection, identification, location, and tracking applications after more than ten years of development. However, its application still suffers from technology bottlenecks, which must be solved and perfected to eliminate the key problems of the technology. This article investigates WSN acquisition nodes and analyzes the relationship between the frequency and actual pressure values of sensor nodes. The sensitive mechanism of the surface acoustic wave (SAW) based on a micro force sensor is researched, and the principle of least squares method is used to establish a transformation model of frequency and pressure for the SAW sensor. According to the model, polyfit function and matrix calculation are selected to solve and calculate the estimate of the polynomial coefficients, which simulate the data acquisition of WSN nodes and draw a polynomial curve fitting. The actual SAW sensor is tested to demonstrate the reasonableness of the device stability in WSNs.

Optimization of Sensitivity Induced by Substrate Strain Rate for Surface Acoustic Wave Yarn Tension Sensor

In this paper, we propose a novel sensitivity optimization design scheme for the yarn tension sensor using surface acoustic wave (SAW) device by improving the strain rate of the SAW yarn tension sensor substrate. The yarn tension sensor, operating at 169.4 MHz, is designed as an oscillator fabricated on a 42°Y-X quartz substrate. Based on regression analysis and finite-element analysis, two mathematical models are established and a linear programming model is built to obtain the best sensitivity. Moreover, the determination coefficients of the two mathematical models both are >0.99, which means that the regression models fit the experimental data exactly. The linear programming results show that the maximum sensitivity will be achieved when the SAW yarn tension sensor substrate length is 19 mm and its width is 3 mm within a fixed interval of the substrate size. The SAW yarn tension sensor with the size of 19 mm × 3 mm was fabricated. Experimental results show that the actual optimal sensitivity 3.13 kHz/g was obtained, confirming that the sensitivity optimization design scheme is effective and applicable.