Dynamic phase compensation for Non-linear Vibroseis using “Phase Only” signature deconvolution.

Author(s):  
*Art Siewert ◽  
Paul Hewitt ◽  
Scott Hess
2021 ◽  
Author(s):  
Georg Woltersdorf ◽  
Rouven Dreyer ◽  
Niklas Liebing ◽  
Chris Körner ◽  
Martin Wagener

Abstract Frequency multiplication is a process where harmonic multiples of the input frequency are generated. It is usually achieved in non-linear electronic circuits or transmission lines. Such elements enable the up-conversion of electronic signals to GHz frequencies and are essential for frequency synthesizers and communication devices. Circuits based on the propagation and interaction of spin waves are a promising alternative to conventional electronics. Unfortunately, these systems usually require direct driving in the GHz range as magnonic frequency up-conversion is restricted to a few harmonics only. Here we show that the ferromagnetic material itself can act as a six octave spanning frequency multiplier. By studying low frequency magnetic excitations in a continuous ferromagnetic layer we show that the non-linearity of magnetization dynamics combined with disorder in the ferromagnet leads to the emergence of a dynamic phase generating high harmonics. The demonstrated broad band frequency multiplication opens exciting perspectives for magnonic and spintronic applications since the frequency is up-converted from MHz into GHz frequencies within the magnetic medium itself. Due to the ease at which magnetic media can be structured and modified spatially (and reversibly) we anticipate that a tailored non-linear dynamic phase can be engineered e.g. to stabilize magnetic solitons.


2013 ◽  
Vol 746 ◽  
pp. 357-362 ◽  
Author(s):  
M.Y. Ismail ◽  
M. Hashim Dahri

The operation of the radar technology is based on the mechanical movement of the antenna. To overcome the flaw of the mechanical movement an electronically tunable reflectarray antenna based on non-linear properties of Liquid Crystal materials has been introduced. This paper presents a detailed analysis of the tunability performance of different X-band reflectarray resonant elements printed on 1 mm thick grounded Liquid Crystal materials. Dynamic phase range and frequency tunabilty of rectangular, dipole and ring elements have been investigated by using CST computer model. Non-linear material properties have been used to develop an algorithm based on Method of Moment, for dynamic phase distribution of three resonant elements. It has been shown that the ring element offers a maximum dynamic phase range of 248° as compared to dipole and rectangular elements which offer 238° and 160° respectively. Moreover a maximum frequency tunabilty of 796 MHz, 784 MHz and 716 MHz can be achieved for rectangular, dipole and ring elements respectively with a dielectric anisotropy of 0.45. Waveguide simulator measurements of passive reflectarray unit cells demonstrate that rectangular element is observed to offer a minimum reflection loss of 1.6 dB as compared to dipole and ring elements which offer 3.3 dB and 3.6 dB respectively.


2022 ◽  
Author(s):  
Chunsheng Guan ◽  
RUI FENG ◽  
Badreddine Ratni ◽  
XUMIN DING ◽  
Jianjia Yi ◽  
...  

Author(s):  
Cory Hendrickson ◽  
Robert T. M’Closkey

Modulated-demodulated control is an effective method for asymptotic disturbance rejection and reference tracking of periodic signals, however, conventional static phase compensation often limits the loop gain in order to avoid sensitivity function peaking in a neighborhood of the frequencies targeted for rejection or tracking. This paper introduces dynamic phase compensation for modulated-demodulated control which improves disturbance rejection characteristics by inverting the plant phase in a neighborhood of the control frequency. Dynamic phase compensation is implemented at baseband which enables the use of low-bandwidth compensators to invert high frequency dynamics. Both static and dynamic phase compensation methods are used to demonstrate a novel application of repetitive control for pulsed jet injection. In this application pulsing an injectant has been shown to produce advantageous effects such as increased mixing in many energy generation and aerospace systems. The sharpness of the pulse can have a large impact on the effectiveness of control. Modulated-demodulated control is used to maximize the sharpness of a pulsed jet of air using active forcing by tracking a square wave in the jet’s temporal velocity profile.


1967 ◽  
Vol 28 ◽  
pp. 105-176
Author(s):  
Robert F. Christy

(Ed. note: The custom in these Symposia has been to have a summary-introductory presentation which lasts about 1 to 1.5 hours, during which discussion from the floor is minor and usually directed at technical clarification. The remainder of the session is then devoted to discussion of the whole subject, oriented around the summary-introduction. The preceding session, I-A, at Nice, followed this pattern. Christy suggested that we might experiment in his presentation with a much more informal approach, allowing considerable discussion of the points raised in the summary-introduction during its presentation, with perhaps the entire morning spent in this way, reserving the afternoon session for discussion only. At Varenna, in the Fourth Symposium, several of the summaryintroductory papers presented from the astronomical viewpoint had been so full of concepts unfamiliar to a number of the aerodynamicists-physicists present, that a major part of the following discussion session had been devoted to simply clarifying concepts and then repeating a considerable amount of what had been summarized. So, always looking for alternatives which help to increase the understanding between the different disciplines by introducing clarification of concept as expeditiously as possible, we tried Christy's suggestion. Thus you will find the pattern of the following different from that in session I-A. I am much indebted to Christy for extensive collaboration in editing the resulting combined presentation and discussion. As always, however, I have taken upon myself the responsibility for the final editing, and so all shortcomings are on my head.)


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