ISSN

ISSN 0860-8229

Wydawcy

Polish Academy of Sciences Committee on Metrology and Scientific Instrumentation

Słowa kluczowe:
checkweigher
weighing method
signal processing
high accuracy

A checkweigher is an automatic machine to measure the weight of in-motion
products. It is usually located around the end of the production process
and ensures the weight of a product within specified limits. Any products
are taken out of line if their weights are out of the specified limits. It
is usually equipped with an optical device. It is used to make a trigger
to set the time duration to allow a product to move completely on the
weigh belt for sampling the weight. In this paper, a new method of mass
measurement for checkweighers is proposed which uses just signal
processing without the optical device. The effectiveness of the method is
shown through experiments. Also a possibility of faster estimation of
weight is shown.

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Słowa kluczowe:
Hilbert spaces
generalized sampling
reconstruction
generalized inverse

This paper considers the problem of reconstructing a class of generalized
sampled signals of which a special case occurs in, e.g., a generalized
sampling system due to non-ideal analysis basis functions. To this end, we
propose an improved reconstruction system and a reconstruction algorithm
based on generalized inverse, which can be viewed as a reconstruction
method that reduces reconstruction error as well. The key idea is to add
an additional channel into a generalized sampling system and apply the
generalized inverse theory to the reconstruction algorithm. Finally, the
approach is applied, respectively, to an oscilloscope, which shows the
proposed method yields better performance as compared to the existing
technique.

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Słowa kluczowe:
noise signal
correlation receiver
Hilbert spaces

A real narrowband noise signal representation in the form of an analytical
signal in the Hilbert space is presented in the paper. This analytical
signal is illustrated in a variable complex plane as a mark with defined
amplitude, phase, pulsation and instantaneous frequency. A block diagram
of a broadband product detector in a quadrature system is presented.
Measurement results of an autocorrelation function of a noise signal are
shown and the application of such solution in a noise radar for precise
determination of distance changes as well as velocities of these changes
are also presented. Conclusions and future plans for applications of the
presented detection technique in broadband noise radars bring the paper to
an end.

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Słowa kluczowe:
sinewave parameter estimation
amplitude and phase measurements
seven parameter sine fit
ellipse fit
spectral sinc fit

In this paper, a comparison analysis of three different algorithms for the
estimation of sine signal parameters in two-channel common frequency
situations is presented. The relevance of this situation is clearly
understood in multiple applications where the algorithms have been
applied. They include impedance measurements, eddy currents testing, laser
anemometry and radio receiver testing for example. The three algorithms
belong to different categories because they are based on different
approaches. The ellipse fit algorithm is a parametric fit based on the XY
plot of the samples of both signals. The seven parameter sine fit
algorithm is a least-squares algorithm based on the time domain fitting of
a single tone sinewave model to the acquired samples. The spectral sinc
fit performs a fitting in the frequency domain of the exact model of an
acquired sinewave on the acquired spectrum. Multiple simulation situations
and real measurements are included in the comparison to demonstrate the
weaknesses and strong points of each algorithm.

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Słowa kluczowe:
hard coal mines
rescue systems
communication systems
trapped miner localizer

Paper deals with the new localizer GLOP2 designed for detection of the
miners trapped in underground hard coal mines. The results of a field test
conducted in coal mine BOBREK show that the presented localizer allows for
efficient measurement of the distance between a trapped miner and the
rescuer in the range of up to 15 m.

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Słowa kluczowe:
digital filter implementation
digital filter word length effects
notch digital filters

Many studies have been developed aiming to improve digital filters
realizations, recurring to intricate structures and analyzing
probabilistically the error's behavior. The work presented in this paper
analyzes the feasibility of fixed-point implementation of classical
infinite impulse response notch filters: Butterworth, Chebyshev I and II,
and elliptic. To scrutinize the deformations suffered for distinct design
specifications, it is assessed: the effect of the quality factor and
normalized cut-off frequency, in the number of significant bits necessary
to represent the filter's coefficients. The implications brought to FPGA
implementation are also verified.
The work focuses especially on the implementation of power line notch filters
used to improve the signal-to-noise ratio in biomedical signals. The
results obtained, when quantizing the digital notch filters, show that by
applying second-order sections decomposition, low-order digital filters
may be designed using only part of double precision capabilities.
High-order notch filters with harsh design constraints are implementable
using double precision, but only in second-order sections. Thus, it is
revealed that to optimize computation time in real-time applications, an
optimal digital notch filter implementation platform should have variable
arithmetic precision.
Considering these implementation constraints, utmost operation performance is
finally estimated when implementing digital notch filters in Xilinx
Virtex-5 field-programmable gate arrays. The influence of several design
specifications, e.g. type, and order, in the filter's behavior was
evaluated, namely in regard to order, type, input and coefficient number
of bits, quality factor and cut-off frequency. Finally the implications
and potential applications of such results are discussed.

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Słowa kluczowe:
wavelet
Fourier transform
geometrical surface structure

Nowadays a geometrical surface structure is usually evaluated with the use
of Fourier transform. This type of transform allows for accurate analysis
of harmonic components of surface profiles. Due to its fundamentals,
Fourier transform is particularly efficient when evaluating periodic
signals. Wavelets are the small waves that are oscillatory and limited in
the range. Wavelets are special type of sets of basis functions that are
useful in the description of function spaces. They are particularly useful
for the description of non-continuous and irregular functions that appear
most often as responses of real physical systems. Bases of wavelet
functions are usually well located in the frequency and in the time
domain. In the case of periodic signals, the Fourier transform is still
extremely useful. It allows to obtain accurate information on the analyzed
surface. Wavelet analysis does not provide as accurate information about
the measured surface as the Fourier transform, but it is a useful tool for
detection of irregularities of the profile. Therefore, wavelet analysis is
the better way to detect scratches or cracks that sometimes occur on the
surface. The paper presents the fundamentals of both types of transform.
It presents also the comparison of an evaluation of the roundness profile
by Fourier and wavelet transforms.

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Słowa kluczowe:
fractional differential equations
fractional differential systems
Fourier transform method
identification methods

This paper presents a study of the Fourier transform method for parameter
identification of a linear dynamic system in the frequency domain using
fractional differential equations. Fundamental definitions of fractional
differential equations are briefly outlined. The Fourier transform method
of identification and their algorithms are generalized so that they
include fractional derivatives and integrals.

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Słowa kluczowe:
metrology
Moiré techniques
fringe analysis
phase measurement
phase shifting technique
Carré equation

The present work offers new equations for phase evaluation in
measurements. Several phase-shifting equations with an arbitrary but
constant phase-shift between captured intensity signs are proposed. The
equations are similarly derived as the so called Carré equation. The idea
is to develop a generalization of the Carré equation that is not
restricted to four images. Errors and random noise in the images cannot be
eliminated, but the uncertainty due to their effects can be reduced by
increasing the number of observations. An experimental analysis of the
errors of the technique was made, as well as a detailed analysis of errors
of the measurement. The advantages of the proposed equation are its
precision in the measures taken, speed of processing and the immunity to
noise in signs and images.

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Słowa kluczowe:
Expanding Systems
conditions and accuracy of action

The interesting properties of a class of expanding systems are discussed.
The operation of the considered systems can be described as follows: the
input signal is processed by a linear dynamic converter in subsequent time
intervals, each of them is equal to Ti. Processing starts at the moments n
· Ti, always after zeroing of converter initial conditions. For smooth
input signals and a given transfer function of the converter one can
suitably choose Ti and the gain coefficient in order to realize the
postulated linear operations on input signals, which is quite different
comparing it to the operation realized by the converter. The errors of
postulated operations are mainly caused by non-smooth components of the
input signal. The principles for choice of system parameters and rules for
system optimization are presented in the paper. The referring examples are
attached too.

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Słowa kluczowe:
SI system
base units
quantum standards

The possibility or even necessity of revising definitions of some of the
base units of the present SI has been discussed over the past 15 years.
The last General Conference of Weights and Measures (2007) recommended to
redefine the kilogram, the ampere, the kelvin, and the mole using fixed
values of the fundamental constants by the time of the next General
Conference in 2011. This paper is a review of proposals of new definitions
of units of mentioned quantities and arguments voting for particular
variants of definitions. Most relevant papers for this review have been
published by Metrologia, the international journal appointed at the BIPM,
and many other useful pieces of information are available on www pages of
the BIPM. The author notes that not only new definitions have been
discussed but as well as the set of the base units of the SI. It means a
replacement of the ampere by the volt or the kelvin by the joule.
Decisions concerning new definitions are not made and the discussions are
still open.

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Słowa kluczowe:
brake system
surface wear
surface topography

The use of surface analysis to investigate brake elements shows how a pair
in contact works and wears out during regular operation. The main purpose
of this paper is to describe the asperities from initial state to a moment
when further use of the drum and shoe is not possible. Between exchange of
vital brake elements a truck with total mass exceeding 3.5 tons can cover
as many as 300 000 kilometres. Use of brakes during the first 1000
kilometres after maintenance should be rather gentle with possibly
intensive use of engine brake installed in the truck itself, because if
this rule is not adhered to it may lead to a significant decrease of the
braking force and on the surface of the pair in contact a layer will
appear that is not possible to wear off and that will make it impossible
to stop a truck using brakes. In that condition the shoe should be
immediately replaced and the drum should be remachined (by turning) to a
repair dimension. In the paper the condition and analysis of a surface
after different course of exploitation was presented.

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Słowa kluczowe:
measurement uncertainty
confidence level
statistical distributions

Referring to the Guide to the Expression of Uncertainty in Measurement
(GUM), the paper proposes a theoretical contribution to assess the
uncertainty interval, with relative confidence level, in the case of n
successive observations. The approach is based on the Chi-square and
Fisher distributions and the validity is proved by a numerical example.
For a more detailed study of the uncertainty evaluation, a model for the
process variability has been also developed.

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Editor-in-Chief

- Janusz SMULKO, Gdańsk University of Technology, Poland

- Andrzej ZAJĄC, Chairman, Military University of Technology, Poland
- Bruno ANDO, University of Catania, Italy
- Martin BURGHOFF, Physikalisch-Technische Bundesanstalt, Germany
- Marcantonio CATELANI, University of Florence, Italy
- Numan DURAKBASA, Vienna University of Technology, Austria
- Domenico GRIMALDI, University of Calabria, Italy
- Laszlo KISH, Texas A&M University, USA
- Eduard LLOBET, Universitat Rovira i Virgili, Tarragona, Spain
- Alex MASON, Liverpool John Moores University, The United Kingdom
- Subhas MUKHOPADHYAY, Massey University, Palmerston North, New Zealand
- Janusz MROCZKA, Wrocław University of Technology, Poland
- Antoni ROGALSKI, Military University of Technology, Poland
- Wiesław WOLIŃSKI, Warsaw University of Technology, Poland

- Zbigniew BIELECKI, Military University of Technology, Poland
- Vladimir DIMCHEV, Ss. Cyril and Methodius University, Macedonia
- Krzysztof DUDA, AGH University of Science and Technology, Poland
- Janusz GAJDA, AGH University of Science and Technology, Poland
- Teodor GOTSZALK, Wrocław University of Technology, Poland
- Ireneusz JABŁOŃSKI, Wrocław University of Technology, Poland
- Piotr JASIŃSKI, Gdańsk University of Technology, Poland
- Piotr KISAŁA, Lublin University of Technology, Poland
- Manoj KUMAR, University of Hyderabad, Telangana, India
- Grzegorz LENTKA, Gdańsk University of Technology, Poland
- Czesław ŁUKIANOWICZ, Koszalin University of Technology, Poland
- Rosario MORELLO, University Mediterranean of Reggio Calabria, Italy
- Fernando PUENTE LEÓN, University Karlsruhe, Germany
- Petr SEDLAK, Brno University of Technology, Czech Republic
- Hamid M. SEDIGHI, Shahid Chamran University of Ahvaz, Ahvaz, Iran
- Roman SZEWCZYK, Warsaw University of Technology, Poland

- Andrzej Stankiewicz, Gdańsk University of Technology, Poland

- Agnieszka Kondratowicz, Gdańsk University of Technology, Poland

Editorial Office of Metrology and Measurement Systems

Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics

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