Distributed broad-band frequency translator and its use in a 1-3-GHz coherent reflectometer

1998 ◽  
Vol 46 (12) ◽  
pp. 2244-2250 ◽  
Author(s):  
P. Akkaraekthalin ◽  
S. Kee ◽  
D.W. Van Der Weide
Keyword(s):  
Broad Band ◽  
Band Frequency

Broad-band frequency references in the near-infrared: Accurate dual comb spectroscopy of methane and acetylene

2013 ◽  
Vol 118 ◽  
pp. 26-39 ◽  
Author(s):  
A.M. Zolot ◽  
F.R. Giorgetta ◽  
E. Baumann ◽  
W.C. Swann ◽  
I. Coddington ◽  
...  
Keyword(s):  
Near Infrared ◽  
Broad Band ◽  
Band Frequency

scholarly journals Frequency multiplication by collective nano-scale spin wave dynamics

2021 ◽  
Author(s):  
Georg Woltersdorf ◽  
Rouven Dreyer ◽  
Niklas Liebing ◽  
Chris Körner ◽  
Martin Wagener
Keyword(s):  
Broad Band ◽  
Ferromagnetic Layer ◽  
Low Frequency ◽  
Ferromagnetic Material ◽  
Frequency Multiplier ◽  
Frequency Multiplication ◽  
Band Frequency ◽  
Promising Alternative ◽  
Dynamic Phase ◽  
Non Linear

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.

Payload Pendulation Reduction Using a Variable-Geometry-Truss Architecture with LQR and Fuzzy Controls

2003 ◽  
Vol 9 (7) ◽  
pp. 805-837 ◽  
Author(s):  
Paolo Dadone ◽  
Walter Lacarbonara ◽  
Ali H. Nayfeh ◽  
Hugh F. Vanlandingham
Keyword(s):  
Control Point ◽  
Broad Band ◽  
Ship Motions ◽  
Control Input ◽  
Variable Geometry ◽  
Linear Quadratic ◽  
Control Laws ◽  
Band Frequency ◽  
Input Acceleration ◽  
Variable Geometry Truss

We investigate the feasibility of a variable-geometry truss (VGT) based architecture for suppressing payload pendulations in ship-mounted cranes. The VGT assembly is conceived to be retrofitted onto the boom tip of ship-mounted cranes. A simplified planar model is developed. A control point along the cable hoisting the payload is constrained to move along a straight path with a given control input (acceleration) imparted via the actuators embedded in the VGT assembly. Control laws based on either linear quadratic or fuzzy control methodologies are developed in order to minimize an assigned cost functional. Their effectiveness is compared through extensive numerical simulations. The performance of the VGT architecture and associated control laws is analyzed when the crane is subject to the most severe combination of resonant excitations: a primary resonant roll excitation at the natural frequency of the controlled system, and a principal-parametric resonant heave excitation, both corresponding to sea state three and higher. The proposed strategy exhibits enough control authority over the system dynamics, greatly reducing the severe and undesirable resonant pendulations caused by the ship motions in a broad-band frequency range. Moreover, its disturbance-rejection capabilities are exerted with feasible control efforts, which are localized in the segment of the crane where they are needed.

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