Phase Sensitive Detection Based on FPAA

Application of FPAA (field programmable analog array) for the construction of phase-sensitive detector is described. The working principle of the phase sensitive detector is introduced. With software called Anadigmdesigner2, a signal selection circuit, a inverting circuit, a rectifier and a low pass filter circuit are achieved. The simulation of the phase-sensitive detector circuit designed is made. Phase rang from 75º to 115 º, phase errors detected are below ±0.392%.

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Eddy Current Detection for Weld Defect and Automatic Separating System for Defective HFW Pipe

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.457-458.344 ◽

2013 ◽

Vol 457-458 ◽

pp. 344-349

Author(s):

Xiao Qin Shen ◽

Fu Sheng Yu ◽

Ying Bao

Keyword(s):

Eddy Current ◽

Pass Filter ◽

Low Pass Filter ◽

Weld Defect ◽

Low Pass ◽

Phase Sensitive ◽

Welded Pipe ◽

Phase Sensitive Detector ◽

The Mathematical Model ◽

Current Detection

An eddy current detection and automatic separating system is developed to defect the weld defects in HFW pipe and separate the defective pipe. Application of phase sensitive detector, the pure signal of the weld defect is obtained through a low-pass filter. The information of the weld defect signal, the displacement of flying saw and the welding speed of welded pipe are fused together. The mathematical model is established for unfixed length truncation of the defective welded pipe. An automatic separating system is designed to cut and separate the defective welded pipes in the production line. The practice shows that this system can accurately detect the weld defect, cut the welded pipe in the perfect position and maximumly reserve the welded pipe without defect. This detection and separating system can improve the quality of the welded pipes and avoid the waste.

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FILTERING APPLICATIONS OF FIELD PROGRAMMABLE ANALOG ARRAYS

Journal of Circuits System and Computers ◽

10.1142/s021812669800016x ◽

1998 ◽

Vol 08 (03) ◽

pp. 337-353 ◽

Cited By ~ 2

Author(s):

O. A. PALUSINSKI ◽

D. M. GETTMAN ◽

D. ANDERSON ◽

H. ANDERSON ◽

C. MARCJAN

Keyword(s):

Cmos Technology ◽

Error Performance ◽

Pass Filter ◽

Low Pass Filter ◽

Additional Information ◽

Programmable Analog ◽

Model Predictions ◽

Field Programmable ◽

Low Pass ◽

Analog Arrays

A Field Programmable Analog Array (FPAA), built in CMOS technology, contains uncommitted operational amplifiers, switches, and capacitors. A FPAA containing banks of programmable switched capacitors (SC) can be used to build filters for analog signals as well as a large number of diverse analog applications. The parameters of a given application, such as a filter, are functions of the capacitor values. Manufacturing and quantization errors may result in capacitor values in the FPAA other than those required by the application. For an FPAA to be a viable substitute for dedicated devices we must examine the error performance of the implementation. Such performance analysis can be built into the software to provide circuit designers with additional information. A methodology is described for determining a bound for the filter error as a function of capacitor errors and capacitor sizes. An example of detailed analysis for a low pass filter is included. Measurements of a low-pass filter implemented using Motorola's prototype FPAA compared favorably with the model predictions.

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Weak Signal Detection System Based on Lock-in Amplifier Technology

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.389.489 ◽

2013 ◽

Vol 389 ◽

pp. 489-493

Author(s):

Yong Lv ◽

Chun Hui Niu ◽

Yue Qiang Li ◽

Qing Shan Chen ◽

Xiao Ying Li ◽

...

Keyword(s):

Signal Detection ◽

Detection System ◽

Signal To Noise Ratio ◽

Weak Signal ◽

Weak Signal Detection ◽

Pass Filter ◽

Low Pass Filter ◽

Low Pass ◽

Phase Sensitive ◽

Lock In

In order to detect the weak signal deeply buried in the noise, a weak signal detection system based on lock-in amplifier is proposed. The system includes the preamplifier circuit, active low pass filter circuit, AC amplifying circuit and phase sensitive demodulation circuit. Test results show that it can greatly increase the signal-to-noise ratio (SNR) up to 12.7db.

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MATHEMATICAL DESCRIPTION OF DIFFERENTIAL EQUATION SOLVING ELECTRICAL CIRCUITS

Journal of Circuits System and Computers ◽

10.1142/s0218126609005484 ◽

2009 ◽

Vol 18 (05) ◽

pp. 985-991 ◽

Cited By ~ 2

Author(s):

K. NAKKEERAN

Keyword(s):

Differential Equation ◽

Differential Equations ◽

Nonlinear Differential Equations ◽

Time Varying ◽

Pass Filter ◽

Low Pass Filter ◽

Electrical Circuits ◽

Equation Solving ◽

Low Pass ◽

Working Principle

We show that the working principle of the differential equation solving analog electrical circuits is exactly the same as the Picard's method available for numerically solving the ordinary differential equations. The integrator circuit (low-pass filter) uses an initial condition and electrical input signal to generate the Maclaurin's series of a time varying function in recursion. This direct connection between the differential equation solving electrical circuits and Picard's method can be exploited to simplify the procedure of Picard's method to solve any order linear and nonlinear differential equations.

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Design of Tunable F-P Filter Driver Based on FPGA

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.602-605.2680 ◽

2014 ◽

Vol 602-605 ◽

pp. 2680-2683

Author(s):

Xu Han ◽

Peng Wang ◽

Si Wen Cai ◽

Yan Ling Xiong ◽

Kai Yu Zhang

Keyword(s):

Frequency Synthesizer ◽

Frequency Control ◽

Low Cost ◽

Control Word ◽

Pass Filter ◽

Low Pass Filter ◽

Field Programmable ◽

Low Pass ◽

Practical Engineering ◽

Stable Performance

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.

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The Application Research of Six-Axis Force Sensor Used by Trans-Femoral Prosthesis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.683.741 ◽

2013 ◽

Vol 683 ◽

pp. 741-744 ◽

Cited By ~ 3

Author(s):

Hua Long Xie ◽

Fei Li ◽

Guo Cun Kang

Keyword(s):

Force Sensor ◽

Window Function ◽

Femoral Prosthesis ◽

Data Filtering ◽

Application Research ◽

Pass Filter ◽

Low Pass Filter ◽

Type Selection ◽

Low Pass ◽

Working Principle

Intelligent bionic leg (IBL) is an advanced trans-femoral prosthesis. First, the conception and structure component of IBL are introduced. Then, working principle of six-axis force sensor is analyzed in detail. The type selection and design of filter are discussed. In the end, the data filtering of low pass filter based on hamming window function is established and simulation is done. The simulation indicates that force and torque signal has a significant improvement after filtering and the filter designed in the paper is reasonable.

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