Simulation-Based Analysis of Influence of Error on Super-Resolution Optical Inspection

2011 ◽  
Vol 5 (2) ◽  
pp. 167-172
Author(s):  
Ryota Kudo ◽  
◽  
Shin Usuki ◽  
Satoru Takahashi ◽  
Kiyoshi Takamasu ◽  
...  
Keyword(s):  
Standing Wave ◽  
Initial Phase ◽  
Experimental Error ◽  
Phase Error ◽  
Super Resolution ◽  
Resolving Power ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Actual Application ◽  
Rayleigh Limit

Microfabricated structures such as semiconductors and MEMS continue shrinking as nanotechnology expands, demand that measures microfabricated structures has risen. Optics and electron beam have been mainly used for that purpose, but the resolving power of optics is limited by the Rayleigh limit and it is generally low for subwavelength-geometry defects, while scanning electron microscopy requires a vacuum and induces contamination in measurement. To handle these considerations, we propose optical microfabrication inspection using a standing-wave shift. This is based on a super-resolution algorithm in which the inspection resolution exceeds the Rayleigh limit by shifting standing waves with a piezoelectric actuator. While resolution beyond the Rayleigh limit by proposed method has been studied theoretically and realized experimentally, we must understand the influence of experimental error factors and reflect this influence in the calibration when actual application is constructed. The standing-wave pitch, initial phase, and noise were studied as experimental error factors. As a result, it was confirmed that super-resolution beyond the Rayleigh limit is achievable if (i) standingwave pitch error was 5% when standing-wave pitch was 300 nm or less and (ii) if initial phase error was 30° when standing-wave pitch was 300 nm. Noise accumulation was confirmed in studies of the noise effect, and a low-pass filter proved effective against noise influence.

Adaptive Robust Control of Speed Sensorless Permanent Magnet Linear Synchronous Motor

2013 ◽  
Vol 385-386 ◽  
pp. 862-866
Author(s):  
Ren Jie Yang ◽  
Si Jia Yu ◽  
Hong Bing Yang ◽  
Chuan Sheng Tang ◽  
Yue Hong Dai
Keyword(s):  
Sliding Mode ◽  
Dynamic Performance ◽  
Phase Error ◽  
Adaptive Robust Control ◽  
Sliding Mode Observer ◽  
Stable Theory ◽  
State Variables ◽  
Motor Speed ◽  
Pass Filter ◽  
Low Pass Filter

In order to improve the dynamic performance of PMLSM, an adaptive robust controller is presented. Meanwhile, the stability of the system is proved by Lyapunov stable theory. The presented controller contains no other motor parameters except state variables. S-function based sliding mode observer is proposed to achieve the estimation of motor speed. The introduction of S-function in the observer can solve the chattering phenomenon caused by traditional sliding mode observer, and solve the amplitude and phase error caused by low-pass filter. Finally, simulation results verify the effectiveness of the proposed control scheme.

scholarly journals Improved harmonic detection method based on ip-iq theory

2021 ◽  
Vol 261 ◽  
pp. 01028
Author(s):  
Zhisen Yao ◽  
Guige Gao
Keyword(s):  
Detection Method ◽  
Phase Error ◽  
Response Speed ◽  
Detection Accuracy ◽  
Harmonic Detection ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
In Series ◽  
Filtering Effect

Based on the traditional ip-iq harmonic detection theory, the accuracy of harmonic detection is easily affected by the phase-locked loop (PLL) output phase error, and the single low-pass filter (LPF) detection accuracy and filtering effect cannot be simultaneously. In this paper, an improved harmonic detection method based on the second-order generalized integrator-frequency locked loop (SOGI-FLL) technique is proposed to generate sine and cosine signals with the same frequency as the grid voltage; The traditional low-pass filter and average filter are used in series to improve the response speed and accuracy. Through theoretical analysis of the improved harmonic detection method and simulation in MATLAB environment, the theory and simulation results prove the effectiveness of the improved method.

ANALISA GANGGUAN FREKUENSI RADIO DAN FREKUENSI PENERBANGAN DENGAN METODA SIMULASI

2014 ◽  
Vol 6 (2) ◽  
pp. 54-67
Author(s):  
Benriwati Maharmi
Keyword(s):  
Standing Wave ◽  
Voltage Standing Wave Ratio ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass

Kisaran frekuensi radio komersil dan frekuensi penerbangan berdekatan sehingga berpotensi untuk terganggu. Kondisi tersebut bisa membahayakan keselamatan penerbangan karena tidak jelasnya informasi yang diterima oleh pilot. Tujuan penelitian ini mengkaji potensi gangguan frekuensi pemancar radio terhadap frekuensi penerbangan, menggunakan metoda simulasi. Gangguan dilihat dari nilai Voltage Standing Wave Ratio (VSWR) yang terjadi pada hasil simulasi sehingga dapat mengidentifikasi apakah pengguna radio frekuensi sesuai dengan aturan yang ditetapkan. Informasi dari simulasi juga dapat mengetahui mode dari modulasinya sehingga diketahui jenis intermodulasi dan pemancar-pemancar radio penyebabnya. Dari hasil simulasi dengan menggunakan VSWR ini juga dapat disimpulkan bahwa stasiun radio yang beroperasi perangkatnya sudah memenuhi standar dan harus senantiasa diperiksa kondisi perangkatnya untuk menjaga linearitas jaringannya agar emisi tersebar (spourius emission) yang terdiri dari harmonisa, intermodulasi, parasitik dapat dikendalikan level dayanya. Untuk mengatasi gangguan frekuensi radio, disarankan menggunakan peralatan berupa low pass filter untuk meminimalkan besarnya level frekuensi intermodulasi sehingga tidak mengganggu frekuensi existingnya.

A ZERO PHASE-LAG HOMODYNE DEMODULATION TECHNIQUE FOR SYNCHRONOUS MEASUREMENT APPLICATIONS AND ITS FPGA IMPLEMENTATION

2005 ◽  
Vol 14 (04) ◽  
pp. 771-791 ◽  
Author(s):  
B. DAM ◽  
K. BANERJEE ◽  
K. MAJUMDAR ◽  
R. BANERJEE ◽  
D. PATRANABIS
Keyword(s):  
A Priori ◽  
Phase Error ◽  
Time Lag ◽  
Fpga Implementation ◽  
Phase Lag ◽  
Processor Time ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Square Wave ◽  
Low Pass

A simple homodyne direct digital demodulation technique that is insensitive to sensor induced phase-error and its innovative FPGA implementation are presented here. This novel demodulation scheme does not need a low pass filter; thereby the inherent filter time lag is eliminated. A direct digital read-out of the demodulated signal, i.e., the measurand value, is obtained through analog-to-digital conversion of the modulated signal at an instant that coincides with its peak. This peak sampling eliminates the processor time required in quadrature demodulators to obtain the measurand from the in-phase and quadrature components. For this purpose a quadrature square wave is first generated from the reference carrier. Digital measures of carrier time period and sensor induced time lag/lead are used to ensure that the rising edges of this quadrature square wave coincide with the peak instants of the modulated signal. The required sampling instants for digitization of the modulated signal are generated in synchronism with its rising edges. The digital read-out of the measurand is directly obtained without taking recourse to the standard sequence of multiplication, low-pass filtering and the subsequent processing common in existing synchronous phase-sensitive demodulators. With an a priori knowledge of the sensor-type used, this innovative FPGA-based implementation accommodates sensors introducing lagging or leading phase-shift in the modulated carrier.

Design of Programmable Wideband Low Pass Filter with Continuous-Time/Discrete-Time Hybrid Architecture

2017 ◽  
Vol E100.C (10) ◽  
pp. 858-865 ◽  
Author(s):  
Yohei MORISHITA ◽  
Koichi MIZUNO ◽  
Junji SATO ◽  
Koji TAKINAMI ◽  
Kazuaki TAKAHASHI
Keyword(s):  
Discrete Time ◽  
Continuous Time ◽  
Hybrid Architecture ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass
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