Final comments on the quasi-continuous frequency spectrum of the input impedance

1973 ◽  
Vol 340 (1) ◽  
pp. 85-87
Author(s):  
Th. Pasch ◽  
R. D. Bauer
Keyword(s):  
Frequency Spectrum ◽  
Input Impedance ◽  
Continuous Frequency

scholarly journals Pulsar NP 0532: Recent Results on Strong Pulses Obtained at Arecibo

1971 ◽  
Vol 46 ◽  
pp. 103-109
Author(s):  
Carl Heiles ◽  
John M. Rankin
Keyword(s):  
Circular Polarization ◽  
Frequency Spectrum ◽  
Linear Polarization ◽  
The Other ◽  
Average Intensity ◽  
Detailed Structure ◽  
Continuous Frequency

New observations have been made of strong pulses from NP 0532. Linear polarization is typically 25 per cent and circular polarization is less than 10 per cent but definitely not zero. A comparison of pulse shapes at 429.9 and 430.1 MHz showed significant differences in detailed structure and polarization. In another study strong pulses at 318 and 111 MHz did not occur together although a strong pulse at one frequency was accompanied by an above average intensity at the other frequency. Similar behaviour was found at 111 and 74 MHz. We conclude that strong pulses do not have a smooth continuous frequency spectrum.

MICROWAVE COMPLEX RESISTIVITY OF YBCO OVER A CONTINUOUS FREQUENCY SPECTRUM

2003 ◽  
Vol 17 (04n06) ◽  
pp. 830-835
Author(s):  
S. SARTI ◽  
N. TOSORATTI ◽  
R. FASTAMPA ◽  
M. GIURA ◽  
E. SILVA ◽  
...  
Keyword(s):  
Frequency Spectrum ◽  
Imaginary Part ◽  
Fluid Model ◽  
Range Data ◽  
Microwave Range ◽  
Complex Resistivity ◽  
Two Fluid Model ◽  
Continuous Frequency ◽  
Experimental Findings ◽  
Two Fluid

We present measurements of the complex resistivity of YBCO thin filmsas a function of frequency, in the microwave range. Data arecollected through a Corbino disc geometry, allowing for a continuous frequency spectrum in the range 1-20 GHz. We focus on the behaviour of the imaginary part of the resistivity as a function of temperature. We show that it presents a broad peak justbelow Tc, whose amplitude and width depend on the frequency. We also discuss to what extent the experimental findings can be explained using the standard two fluid model, and which are the possible responsibles for the deviations from these predictions.

scholarly journals Efficient Iterative Process based on an Improved Genetic Algorithm for Decoupling Capacitor Placement at Board Level

Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1219 ◽  
Author(s):  
de Paulis ◽  
Cecchetti ◽  
Olivieri ◽  
Piersanti ◽  
Orlandi ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Frequency Spectrum ◽  
Input Impedance ◽  
Iterative Process ◽  
Power Delivery ◽  
Improved Genetic Algorithm ◽  
Decoupling Capacitors ◽  
Power Delivery Network ◽  
Capacitor Placement ◽  
Board Level

To reduce the noise created by a power delivery network, the number, the value of decoupling capacitors and their arrangement on the board are critical to reaching this goal. This work deals with specific improvements, implemented on a genetic algorithm, which used for the optimization of the decoupling capacitors in order to obtain the frequency spectrum of the input impedance in different positions on the network, below previously defined values. Measurements are performed on a specifically manufactured board in order to validate the effectiveness of the proposed algorithm and the optimization results obtained for a specific example board.

scholarly journals Electrical Impedance Measurements of PZT Nanofiber Sensors

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Richard Galos ◽  
Yong Shi ◽  
Zhongjing Ren ◽  
Liang Zhou ◽  
Hao Sun ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Frequency Spectrum ◽  
Material Properties ◽  
Input Impedance ◽  
Electrical Impedance ◽  
Low Noise ◽  
Impedance Measurements ◽  
Conductive Afm ◽  
Microfabrication Techniques

Electrical impedance measurements of PZT nanofiber sensors were performed using a variety of methods over a frequency spectrum ranging from DC to 1.8 GHz. The nanofibers formed by electrospinning with diameters ranging from 10 to 150 nm were collected and integrated into sensors using microfabrication techniques. Special matching circuits with ultrahigh input impedance were fabricated to produce low noise, measurable sensor outputs. Material properties including resistivity and dielectric constant are derived from the impedance measurements. The resulting material properties are also compared with those of individual nanofibers being tested using conductive AFM and Scanning Conductive Microscopy.

Significance of Elastance Variation on Respiratory System Dynamics

2002 ◽  
Author(s):  
A. M. Al-Jumaily ◽  
Y. Al-Fakhri
Keyword(s):  
Dynamic Response ◽  
System Dynamics ◽  
Frequency Spectrum ◽  
Respiratory System ◽  
Input Impedance ◽  
Airway Wall ◽  
Asymmetric Structures ◽  
Asthma Attack ◽  
Lung Structure ◽  
Recursion Formulas

The sensitivity of the respiratory system dynamic response to variations in the wall elastance is investigated. The acoustical approach is used to determine the impedance at the throat using impedance recursion formulas. Both symmetric and asymmetric structures are considered. The response of the lung structure indicates that when the airway wall elastance varies, as the case during an asthma attack, the overall normalized input impedance frequency spectrum could be used to give a reasonable signature for identifying such abnormality.

Obstruction Identification in a Compliant Tube with Application to Airway Passages

2002 ◽  
Vol 8 (5) ◽  
pp. 643-657 ◽  
Author(s):  
A. M. Al-Jumaily ◽  
Y. Du
Keyword(s):  
Frequency Spectrum ◽  
Input Impedance ◽  
Upper Airway ◽  
Resonant Frequencies

Using the acoustic input impedance, an appropriate theoretical technique for identifying constrictions in a tube with wall inertance and elastance being considered is developed. Although the technique could work for various types of tubes, it is applied to identifying occlusion in an upper airway passage. The frequency spectrum of the input impedance is examined for three types of constrictions, namely localized, uniform and gradual models. The result demonstrates that the input impedance resonant frequencies can map the location, severity and degree of the constriction.

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