A new method used for high speed pseudo-random code generating

Author(s):  
Zhanfeng Zhao ◽  
Dong Zhang ◽  
Zhiquan Zhou
Keyword(s):  
2021 ◽  
Vol 11 (13) ◽  
pp. 5787
Author(s):  
Toan-Thang Vu ◽  
Thanh-Tung Vu ◽  
Van-Doanh Tran ◽  
Thanh-Dong Nguyen ◽  
Ngoc-Tam Bui

The measurement speed and measurement accuracy of a displacement measuring interferometer are key parameters. To verify these parameters, a fast and high-accuracy motion is required. However, the displacement induced by a mechanical actuator generates disadvantageous features, such as slow motion, hysteresis, distortion, and vibration. This paper proposes a new method for a nonmechanical high-speed motion using an electro-optic modulator (EOM). The method is based on the principle that all displacement measuring interferometers measure the phase change to calculate the displacement. This means that the EOM can be used to accurately generate phase change rather than a mechanical actuator. The proposed method is then validated by placing the EOM into an arm of a frequency modulation interferometer. By using two lock-in amplifiers, the phase change in an EOM and, hence, the corresponding virtual displacement could be measured by the interferometer. The measurement showed that the system could achieve a displacement at 20 kHz, a speed of 6.08 mm/s, and a displacement noise level < 100 pm//√Hz above 2 kHz. The proposed virtual displacement can be applied to determine both the measurement speed and accuracy of displacement measuring interferometers, such as homodyne interferometers, heterodyne interferometers, and frequency modulated interferometers.


2005 ◽  
Vol 6-8 ◽  
pp. 805-808
Author(s):  
F. Sekine

The blanking of thin sheet metals using progressive dies is an important process on production of precision electronic machine parts. As a model of IC leadframe, an I-shaped and an Lshaped models were blanked and influences of blanking conditions on dimensional accuracy of blanked lead were examined. Furthermore, a mechanical model is proposed to explain the affect of the blanking conditions on product accuracy. In these days, more fine leads are required as electronic machines become more precise and accurate. It must be treated that leads are firmly held for blanking leadframes accurately. In this paper, an effective method of stripper holding leads strongly are discussed and a new method using newly designed stripper is proposed. Consequently the effect of it on lead accuracy is proved.


1999 ◽  
Vol 121 (2) ◽  
pp. 319-323 ◽  
Author(s):  
Teng Guilan ◽  
Fu Haibo ◽  
Zhou Weiyi

Severe vibration and poor positioning accuracy may occur in an indexing cam mechanism operating at a high speed. Torque fluctuation of the input shaft and the resulting fluctuation of kinetic energy of the mechanism may be the major cause of the vibration. In this paper a method is proposed to minimize the fluctuation by using a so-called “speed-varying flywheel” that produces an opposite kinetic energy fluctuation that can counteract the effect of the energy fluctuation. The flywheel is installed on the output shaft of an additional cam-linkage mechanism. The parameter of the cam-linkage mechanism is optimized. An example is given to demonstrate the effectiveness of this method.


Measurement ◽  
2012 ◽  
Vol 45 (8) ◽  
pp. 2135-2140 ◽  
Author(s):  
B. Davoodi ◽  
H. Hosseinzadeh

Author(s):  
L. Yuan ◽  
J. Rastegar

Abstract A new method for the analysis of the effects of structural flexibility on the dynamic behavior of mechanical systems is presented. The developed method is in most part based on “tracing” the “propagation” of the effects of the high frequency motion requirements on the dynamic response characteristics of machines with structural flexibilities, particularly those with closed-loop kinematic structures. The method considers the “filtering” action of structural elements with flexibility. Such filtering of higher frequency motions is shown to have a predictable effect on the steady state motion of such mechanical system. The main advantage of the developed method is that the effects of such flexibilities can be determined without the need to perform the usual dynamics modeling and computer simulations. The method is shown to be very simple and readily implementable. The method is applied to a four-bar linkage mechanism with a longitudinally flexible coupler link. The obtained results are shown to be highly accurate as compared to those obtained by computer simulation. The application of the method to systematic design of machines with structural flexibility for high speed and precision operation, optimal integration of smart (active) materials into the structure of such machines, and some related issues are discussed.


2019 ◽  
Vol 946 ◽  
pp. 782-787
Author(s):  
Vladimir P. Volkov ◽  
Denis Rinatovich Salikhyanov ◽  
Ivan S. Kamantsev ◽  
Aziret A. Shamshiev

Modern press forging manufacture of large steel forgings is moving along the way of increasing service properties and reducing energy-power parameters. This is evidenced by a significant number of works devoted to the study of forging technology with the use of special tools allowing to implement severe plastic deformation. As a result, it is possible to improve significantly the metal structure at the same values of the forge reduction. The paper presents the results of the development and investigation of a new method of forging large steel billets with the intensification of shear deformation and with the use of standard anvils. The analysis of the stress-strain state in comparison with traditional forging scheme on an example of forging billets made of high speed steel R6М5 (State Standard GOST 19265-73) is presented. It is shown that the accumulated degree of shear deformation, as well as the uniformity of its distribution, is higher for the new method with the same reduction values. Approbation of the new method of forging on a hydraulic press was carried out for the blanks made of aluminium alloy D16 (State Standard GOST 21488-97).


2011 ◽  
Vol 400 (3) ◽  
pp. 767-775 ◽  
Author(s):  
Evelyn Png ◽  
WanWen Lan ◽  
Melisa Lazaroo ◽  
Silin Chen ◽  
Lei Zhou ◽  
...  

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