Research on Frequency Conversion ＆ Selective Measurement and Error Correction Algorithms in Grounding Characteristics Measuring System

2012 ◽  
Vol 605-607 ◽  
pp. 1068-1073
Author(s):  
Si Qi Wang ◽  
Xi Wen Chen ◽  
Zi Juan Guo ◽  
Xu Wang
Keyword(s):  
Frequency Conversion ◽  
Phase Error ◽  
Sampling Rate ◽  
Estimation Method ◽  
Signal Amplitude ◽  
Measuring System ◽  
Frequency Resolution ◽  
Frequency Error ◽  
High Precision Measurement ◽  
Data Length

The paper concerns algorithms error and parameters correction technology of frequency conversion＆selective measurement in grounding characteristics measuring system. It analyzes estimation method of signal amplitude phase based on Fourier transform, calculates the sensitive degree of the method to frequency error, and also presents several major parameters for the algorithm, including sampling rate, data length and selection condition of frequency resolution in order to meet the high precision measurement requirements. Furthermore, the paper analyzes correction algorithm of amplitude and phase error caused by unknown nonlinearity of circuit during the practical measurement.

scholarly journals Z-ADALINE based high-precision wide-frequency signal measurement algorithm for power electronic power grid

2020 ◽  
Vol 185 ◽  
pp. 01041
Author(s):  
Wenxiu Wang ◽  
Shuguo Pan ◽  
Jiawei Peng ◽  
Jian Shen ◽  
Min Zhang ◽  
...  
Keyword(s):  
High Precision ◽  
Power Grid ◽  
Phase Error ◽  
Low Frequency ◽  
Frequency Measurement ◽  
Frequency Resolution ◽  
Power Electronic ◽  
High Precision Measurement ◽  
Frequency Signal ◽  
Signal Measurement

Intermittent wind power, photovoltaic and other renewable energies have been paralleled, which makes the phenomena of high-order harmonics and simple harmonics more and more serious in the power system, showing a wide-frequency trend. The existing measurement algorithms mainly aim at signals in midfrequency and low-frequency. Besides, they are lack of a uniform high-precision algorithm for widefrequency measurement. To solve this problem, we propose a high-precision algorithm based on Z-ADALINE. Firstly, Zoom FFT algorithm is used to analyze original sampled signals. This step enables the refinement of its frequency spectrum, and obtains accurate frequency measurement results. At this time, the number of frequencies can also be determined. Secondly, the result of Zoom FFT is used as the input of the adaptive linear neural network(ADALINE). ADALINE can estimate amplitude and phase with high precision. The simulation results show that the proposed algorithm can realize high-precision measurement of frequency, amplitude and phase of wide-frequency signal effectively. Among them, the frequency resolution can be up to 0.3 Hz. The amplitude error is within 1V. Phase error is less than 0.6°. The results may provide some significant references for practical wide-frequency signal measurement in power electronic power grid.

Synchronization between Driving and Illumination Signals in a High Frequency Stroboscopic Imaging System

2011 ◽  
Vol 70 ◽  
pp. 327-332
Author(s):  
Cheng Fei Wang ◽  
Ying Jun Xu ◽  
Fei Peng Zhu ◽  
Xiao Yuan He
Keyword(s):  
Light Source ◽  
High Frequency ◽  
Relative Phase ◽  
Frequency Conversion ◽  
Imaging System ◽  
Phase Error ◽  
Frequency Resolution ◽  
Signal Frequency ◽  
Drive Signals ◽  
The Impact

In a stroboscopic imaging system, in order to make images to be correctly captured the synchronization must be strictly satisfied. Direct digital synthesizer (DDS) is a new frequency synthesizing technique used for creating arbitrary waveforms from a single, fixed-frequency reference clock. It has many advantages such as fast frequency conversion, high resolution of frequency and keeping phase continuous while frequency switches. By applying the DDS technique, this paper presents a method to generate the illumination signal of light source and the drive signal of device, and more attention is paid to how to perform the precise synchronization between the two signals. By adjusting the relative delay of the illumination and the drive signals, the phase can be changed. Allowing a sequence of images depicting the motion over the interval studied to be captured, which yields a complete picture of the vibration of a specimen or the surface structure of a MEMS device. Experimental results show that the high frequency of a signal could be up to 120 MHz with frequency resolution 4μHz. The phase resolution of 2-16 can be achieved by the proposed method. The relative phase error between illumination and driven signals could be down to 2-16. It is relatively easy to a synchronization illumination signal of light source and drive signal of MEMS accurately. However, as the two signals' transmission paths are different, their transmission delays are different also. Accordingly, a phase error would be caused and it would change as the signal frequency changes. Moreover, if the drive signal of external objects is used, the phase error, which is introduced via inaccuracy synchronizing the frequency of signal, would be superposed, indeed. These phase errors would affect the quality of imaging and the accuracy of measurement. In this paper, an effective method to adjust the errors is proposed. By means of specially designed hardware circuit, the error of phase and frequency synchronization between illumination signal of light source and drive signal of MEMS can be adjusted automatically. The proposed method improves the accuracy in synchronism and reduces the impact of the error of signal synchronization in the system. It is proved that the minimum relative phase error between illumination signal of light source and drive signal of MEMS can be reduced by more than 10 times using this method.

scholarly journals Spectral Analysis of Stationary Signals Based on Two Simplified Arrangements of Chirp Transform Spectrometer

Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 65
Author(s):  
Quan Zhao ◽  
Ling Tong ◽  
Bo Gao
Keyword(s):  
Spectral Analysis ◽  
Frequency Conversion ◽  
Frequency Resolution ◽  
Matching Problem ◽  
System Sensitivity ◽  
Deep Space Exploration ◽  
Spectrum Measurement ◽  
Stationary Signals ◽  
Simulation And Experiment ◽  
Remote Sensing Systems

The classical two-channel push-pull chirp transform spectrometer (CTS) has been widely applied in satellite-borne remote sensing systems for earth observation and deep space exploration. In this paper, we present two simplified structures with single M(l)-C(s) CTS arrangements for the spectral analysis of stationary signals. A simplified CTS system with a single M(l)-C(s) arrangement and a time delay line was firstly developed. Another simplified structure of CTS with a M(l)-C(s) arrangement and a frequency conversion channel was also developed for spectral analysis of stationary signals. Simulation and experiment results demonstrate that the two simplified arrangements can both realize spectrum measurement for the stationary signals and obtain the same frequency resolution, amplitude accuracy and system sensitivity as that of the classical two-channel push–pull CTS system. Compared to the classical CTS structure, the two simplified arrangements require fewer devices, save power consumption and have reduced mass. The matching problem between the two channels can be avoided in the two simplified arrangements. The simplified CTS arrangements may have potential application in the spectrum measurement of stationary signals in the field of aviation and spaceflight.

scholarly journals High-Resolution ISAR Imaging and Autofocusing via 2D-ADMM-Net

2021 ◽  
Vol 13 (12) ◽  
pp. 2326
Author(s):  
Xiaoyong Li ◽  
Xueru Bai ◽  
Feng Zhou
Keyword(s):  
Deep Learning ◽  
High Resolution ◽  
Phase Error ◽  
Random Phase ◽  
Back Propagation ◽  
Estimation Method ◽  
Data Driven ◽  
Reconstruction Performance ◽  
Imaging Results ◽  
Isar Imaging

A deep-learning architecture, dubbed as the 2D-ADMM-Net (2D-ADN), is proposed in this article. It provides effective high-resolution 2D inverse synthetic aperture radar (ISAR) imaging under scenarios of low SNRs and incomplete data, by combining model-based sparse reconstruction and data-driven deep learning. Firstly, mapping from ISAR images to their corresponding echoes in the wavenumber domain is derived. Then, a 2D alternating direction method of multipliers (ADMM) is unrolled and generalized to a deep network, where all adjustable parameters in the reconstruction layers, nonlinear transform layers, and multiplier update layers are learned by an end-to-end training through back-propagation. Since the optimal parameters of each layer are learned separately, 2D-ADN exhibits more representation flexibility and preferable reconstruction performance than model-driven methods. Simultaneously, it is able to better facilitate ISAR imaging with limited training samples than data-driven methods owing to its simple structure and small number of adjustable parameters. Additionally, benefiting from the good performance of 2D-ADN, a random phase error estimation method is proposed, through which well-focused imaging can be acquired. It is demonstrated by experiments that although trained by only a few simulated images, the 2D-ADN shows good adaptability to measured data and favorable imaging results with a clear background can be obtained in a short time.

Intelligent Displacement Measuring System for Rock Stratum

2011 ◽  
Vol 103 ◽  
pp. 583-586
Author(s):  
Feng Ling Li ◽  
Jian Hua Rong ◽  
Yu Ping Zhang
Keyword(s):  
Civil Engineer ◽  
Real Time ◽  
Sampling Rate ◽  
Measuring System ◽  
Displacement Sensor ◽  
Rock Stratum ◽  
Baud Rate ◽  
Real Time Clock ◽  
High Sampling Rate ◽  
Displacement System

Measuring rock stratum displacement in dam grouting process is very important. A new displacement system is designed, comprising a programmable microcontroller Atmega16, a new grating capacitive displacement sensor(GCDS), DS1302 real time clock chip and announciator etc. The system has high sampling rate of 9600 baud rate and can trap the displacement equal to 0.001 millimeter in one second. Equipped with mechanical conveyance system, the system can be applied to the civil engineer. The experiment results show the instrument can measure accurately the displacement value and alarm geologic disaster in time, which can conduct continuous and accurate monitoring and provide operation decisions for dam engineers.

scholarly journals PAPR Reduction of FBMC Signals Based on Uniform and Linear PDF Companding Schemes

2021 ◽  
Author(s):  
Srinivas Ramavath ◽  
Umesh Chandra Samal
Keyword(s):  
Theoretical Analysis ◽  
Bit Error Rate ◽  
Error Rate ◽  
Filter Bank ◽  
Phase Error ◽  
Average Power ◽  
Signal Amplitude ◽  
Papr Reduction ◽  
Basic Model ◽  
Filter Bank Multicarrier

Abstract In this paper, two new companders are designed to reduce the ratio of peak to average power (PAPR) experienced by filter bank multicarrier (FBMC) signals. Specifically, the compander basic model is generalized, which alter the distributed FBMC signal amplitude peak. The proposed companders design approach provides better performance in terms of reducing the PAPR, Bit Error Rate (BER) and phase error degradation over the previously existing compander schemes. Many PAPR reduction approaches, such as the µ-law companding technique, are also available. It results in the formation of spectrum side lobes, although the proposed techniques result in a spectrum with fewer side lobes. The theoretical analysis of linear compander and expander transform for a few specific parameters are derived and analyzed. The suggested linear companding technique is analytically analysed using simulations to show that it efficiently decreases the high peaks in the FBMC system.

scholarly journals ANALYSIS AND IMPROVISATION IN EXTRACTING AUDIO SIGNAL AMPLITUDE USING LABVIEW

2020 ◽  
pp. 273-278
Author(s):  
Adarsh V Srinivasan ◽  
Mr. N. Saritakumar
Keyword(s):  
Virtual Instrument ◽  
Sampling Rate ◽  
Audio Signal ◽  
Signal Amplitude ◽  
Audio Signals ◽  
Virtual Instrumentation ◽  
Audio Processing ◽  
Reading And Writing ◽  
Labview Software ◽  
Frequency Sampling

In this paper, either a pre-recorded audio or a newly recorded audio is processed and analysed using the LabVIEW Software by National Instruments. All the data such as bitrate, number of channels, frequency, sampling rate of the Audio are analyzed and improvising the signal by a few operations like Amplification, De-Amplification, Inversion and Interlacing of Audio Signals are done. In LabVIEW, there are a few Sub Virtual Instrument’s available for Reading and Writing Audio in .wav formats and using them and array Sub Virtual Instrument, all the processing are done. KEYWORDS: Virtual Instrumentation (VI), LabVIEW (LV), Audio, Processing, audio array.

An Impact-Based Experimental Setup for Evaluation of Rapid Electromechanical Impedance-Based Structural Health Monitoring

2020 ◽  
Author(s):  
Mohammad Alshaikh Ali ◽  
Eric C. Nolan ◽  
Steven R. Anton ◽  
Mohsen Safaei
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Sampling Rate ◽  
Frequency Resolution ◽  
Experimental Setup ◽  
Frequency Bandwidth ◽  
Electromechanical Impedance ◽  
Excitation Signal ◽  
Structural Health ◽  
The Impact

Abstract This work investigates the application of structural health monitoring (SHM) in a dynamic environment with the electromechanical impedance (EMI) method. Classically, the EMI method monitors civil or mechanical structures for damage in static environments. Advances in data acquisition (DAQ) now allow the possibility of rapid damage detection in dynamic environments. An impact-based experimental setup is developed to create a repeatable dynamic event through a collision between a pneumatically actuated striker bar and a static incident bar instrumented with a piezoelectric transducer. The EMI method is employed to detect the change of state at the interface of the two colliding bars. Experimental results prove the pneumatic launching system is capable of repeatable dynamic events, but the duration of contact is only 0.03 ms and the current DAQ system is incapable of detecting the event. A 3D printed programming material interface is placed at the location of impact to increase the duration of contact to approximately 1 ms. An excitation signal is created to continuously sweep a 0.5 ms chirp signal with a frequency bandwidth from 60–70 kHz (previously identified damage sensitive frequency bandwidth from static testing) for 7.5 seconds. Results indicate that due to the sampling rate and sweep time of the excitation signal, the frequency resolution is not adequate to properly assess if the impact is detected. Improvements in the DAQ hardware must be considered for future work.

scholarly journals Research on Turning Motion Targets and Velocity Estimation in High Resolution Spaceborne SAR

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2201 ◽  
Author(s):  
Xuejiao Wen ◽  
Xiaolan Qiu
Keyword(s):  
High Resolution ◽  
Geometric Modeling ◽  
Phase Error ◽  
Estimation Method ◽  
Velocity Estimation ◽  
Continuous Change ◽  
Straight Line ◽  
Moving Direction ◽  
Turning Motion ◽  
Motion Imaging

The development of high resolution SAR makes the influence of moving target more prominent, which results in defocusing and other unexplained phenomena. This paper focuses on the research of imaging signatures and velocity estimation of turning motion targets. In this paper, the turning motion is regarded as the straight line motion of continuous change of moving direction. Through the analysis of the straight line motion with constant velocity and the geometric modeling of the turning motion in spaceborne SAR, the imaging signatures of the turning motion target are obtained, such as the broken line phenomenon at the curve. Furthermore, a method for estimating the turning velocity is proposed here. The radial velocity is calculated by the azimuth offset of the turning motion target and the azimuth velocity is calculated by the phase error compensated in the refocusing process. The amplitude and direction of the velocity can be obtained by using both of them. The results of simulation and GF-3 data prove the accuracy of the analysis of turning motion imaging signatures, and they also show the accuracy and validity of the velocity estimation method in this paper.

scholarly journals C/N0 Estimator Based on the Adaptive Strong Tracking Kalman Filter for GNSS Vector Receivers

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 739 ◽  
Author(s):  
Shiming Liu ◽  
Sihai Li ◽  
Jiangtao Zheng ◽  
Qiangwen Fu ◽  
Yanhua Yuan
Keyword(s):  
Kalman Filter ◽  
Estimation Method ◽  
Signal Amplitude ◽  
Satellite System ◽  
Static Field ◽  
Weak Signal ◽  
Important Indicator ◽  
Vector Receiver ◽  
Averaging Time ◽  
Global Navigation Satellite

The carrier-to-noise ratio (C/N0) is an important indicator of the signal quality of global navigation satellite system receivers. In a vector receiver, estimating C/N0 using a signal amplitude Kalman filter is a typical method. However, the classical Kalman filter (CKF) has a significant estimation delay if the signal power levels change suddenly. In a weak signal environment, it is difficult to estimate the measurement noise for CKF correctly. This article proposes the use of the adaptive strong tracking Kalman filter (ASTKF) to estimate C/N0. The estimator was evaluated via simulation experiments and a static field test. The results demonstrate that the ASTKF C/N0 estimator can track abrupt variations in C/N0 and the method can estimate the weak signal C/N0 correctly. When C/N0 jumps, the ASTKF estimation method shows a significant advantage over the adaptive Kalman filter (AKF) method in terms of the time delay. Compared with the popular C/N0 algorithms, the narrow-to-wideband power ratio (NWPR) method, and the variance summing method (VSM), the ASTKF C/N0 estimator can adopt a shorter averaging time, which reduces the hysteresis of the estimation results.

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