Research on eye axial length measurement system based on Twyman-Green interferometer combined with digital signal processing

2021 ◽  
Author(s):  
Qi Zhou ◽  
Kang Xu ◽  
Ming-hui Chen ◽  
Hua-zhong Xiang ◽  
Gang Zheng ◽  
...  
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
Measurement System ◽  
Axial Length ◽  
Digital Signal ◽  
Length Measurement

scholarly journals A novel quasi-peak-detector for time-domain EMI-measurements

2005 ◽  
Vol 2 ◽  
pp. 27-32 ◽  
Author(s):  
F. Krug ◽  
S. Braun ◽  
P. Russer
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
Measurement System ◽  
Time Domain ◽  
Electromagnetic Interference ◽  
Digital Signal ◽  
Peak Detection ◽  
Peak Detector ◽  
Measurement Results ◽  
Signal Recording

Abstract. In this paper, an advanced ultra-fast, broadband time domain EMI measurement system is described. Measurements were performed in the 30–1000MHz range. The digital signal processing of EMI measurements allows to emulate in real-time the modes of conventional analogous equipment, e.g. Peak-, Average-, RMS- and Quasi-Peak- Detector. With the presented time domain measurement system the measurement time can be reduced by a factor of 10. A novel signal recording routine for time-domain EMI (TDEMI) measurements and Quasi-Peak-Detection is described. Measurement results obtained from the investigation of a drillmachine, monitor and laptop obtained with the timedomain electromagnetic interference (TDEMI) measurement system are discussed. The results obtained with the described system have been compared with measurements performed with a conventional EMI receiver.

Method of estimation of hidden correlation of narrowband noise signals

2019 ◽  
pp. 34-39 ◽  
Author(s):  
E.I. Chernov ◽  
N.E. Sobolev ◽  
A.A. Bondarchuk ◽  
L.E. Aristarhova
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
New Technology ◽  
Digital Signal ◽  
Measuring Instruments ◽  
Central Frequency ◽  
Pearson Criterion ◽  
Useful Signal ◽  
Band Limited ◽  
Narrowband Noise

The concept of hidden correlation of noise signals is introduced. The existence of a hidden correlation between narrowband noise signals isolated simultaneously from broadband band-limited noise is theoretically proved. A method for estimating the latent correlation of narrowband noise signals has been developed and experimentally investigated. As a result of the experiment, where a time frag ent of band-limited noise, the basis of which is shot noise, is used as the studied signal, it is established: when applying the Pearson criterion, there is practically no correlation between the signal at the Central frequency and the sum of signals at mirror frequencies; when applying the proposed method for the analysis of the same signals, a strong hidden correlation is found. The proposed method is useful for researchers, engineers and metrologists engaged in digital signal processing, as well as developers of measuring instruments using a new technology for isolating a useful signal from noise – the method of mirror noise images.

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