Embedded systems

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25 Νοε 2013 (πριν από 3 χρόνια και 4 μήνες)

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Embedded Systems

The contemporary solutions of measurement and
instrumentation are based on dedicated computer
sy
s
tems, and offer a wide variety of autonomous
services. These services include primarily data
a
c
quisition, information processing, and control,

but
there are several other add
i
tional mechanisms to
achieve high
-
quality overall performance. The
m
a
jority of such applications can be considered as
e
m
bedded systems due to the fact, that in add
i
tion to
the sensors and the actuators, also the dedicated
c
omputer system components are invisibly
embe
d
ded into the hosting environment. The role of
these embedded systems is to measure or identify
the b
e
haviour of their environment, which is
followed by some real
-
time computations to provide
proper cha
r
acterizat
ion, influence and control.

The Department of Measurement and Inform
a
tion
Systems operates seven smaller laboratories working
on problems related to various kinds of e
m
bedded
systems, and hosts the Embedded Inform
a
tion
Technology R
e
search Group of the Hung
arian
Academy of Sciences and the Budapest University
of Technology and Economics.


Calibration Instruments Laboratory


Research interest
:

current, voltage, impedance
mea
s
urement, self
-
calibrating instruments,
calibration of i
n
strument transformers, artifi
cial
impedances.

Staff:

István Zoltán,
associate professor
, Zoltán
Benesóczky, A
n
drás Görg
é
nyi, Balázs Vargha,
senior le
c
turers
, József Dudás,
engineer
, Zoltán
Román, and Zsolt Szepessy as

PhD students
.

Resources and infrastructure
:

DC
-
Calibrator, AC
-
Calib
rator, CT
-
Calibrator, VT
-
Calibrator, Sta
n
dard
CTs, I
m
pedance Analyzer.

Major research and development projects:

The Department has a great tradition in research and
development of precision electrical measurements
and metrology including the co
m
plete innov
ation
process.

The main fields of the research activity:



Current, voltage, impedance and power
mea
s
urement



Self
-
calibrating, self
-
correcting instruments



Calibration of instrument transformers



Artificial impedances

Since the appropriate reference s
tandards did not
exist, or were not available, the high precision
instruments developed between 1980 and 1990
served mainly calibration purposes.

From the beginning of the 90's, the rapid
development of the analogue, digital and mixed
signal processing op
ened new possibilities in
instrumentation. Thanks to this advancing hardware
and software tools, the calibration functions of the
devices could be int
e
grated into the measuring
instruments, and even the automatic self
-
correction
of the errors measured duri
ng the self
-
calibration
process became possible.

Based on these methods the following typical errors
became manageable:



the errors of approximation



calculable errors



measurable errors



errors caused by influence quantities



thermal drift

Thanks to thi
s approach the overall accuracy of the
i
n
struments can be even 1000
-
times better than that
of the built
-
in components. This poss
i
bility basically
changes the principles of develo
p
ment of measuring
instruments.

From the beginning of the 90's, more and more
PhD
students became involved in the research of self
-
calibrating and self
-
correcting measuring
instr
u
ments in the following topics:



Artificial impedances



Self
-
calibrating amplifiers



Correction of thermal dynamic errors



Impedance analysis



Calibration Algo
rithm for Current
-
Output
R
-
2R Ladders



Calibration of power measuring instruments

The self
-
calibrating and self
-
correcting measuring
instruments provide the possibility of low
-
cost and
eff
i
cient remote calibration via Internet, foreseeing
already the techno
logy of the third millennium in
precision measurement and metrology.

The growing development
-
, manufacturing
-
,
marke
t
ing
-
, and after sales service requirements
related to the new, advanced calibration instruments
required a more appropriate organisation,
thus in
1997 the CALIN Electronics Ltd. was established.

Parallel to this, the co
-
operation with the
Depar
t
ment was succes
s
fully continued by CALIN
Electronics Ltd. As a result of the common efforts,
in 1998 a new advanced ge
n
eration of self
-
calibrating an
d self
-
correcting measuring
instruments has been intr
o
duced to the international
market. These instruments are used as national
standards and also for automatic calibration in
manufacturing of current and voltage transformers in
Austria, Brazil, England, G
ermany, Hungary,
Romania, and Taiwan.


Some recent products:


Figure 1.

Instrument Transformer Analyzer
composed of 1 ppm calibrator and programmable
high
-
power art
i
ficial impedance with 101442
settings


Figure 2.

1 ppm Standard Current Transformer

used
in the 0.5….10000 A current range



Figure 3.

Standard Additional Burden for voltage
transformer calibration





Figure 4.

Standard Current Transformer for
calibration of watthour meters


Acknowledgement:
The staff of the laboratory
wishes to express hi
s appreciation to the former
contributors: László Schnell, Endre Tóth, Péter
Osváth, Gyula Korányi, Péter Pataki, Ferenc Nagy,
Zoltán Reguly, László Naszádos, László Gyöngy,
Erik Bohus.



Contact person:

István Zoltán

izoltan@mit.bme.hu

www.mit.bme.hu/~izoltan/






Selected publications:


1.

Zoltán, I., “A Multi
-
Function Standard
Instrument for Current Transformer
Calibration,” OIML, Bulletin, Vol. XXXVI, No.
4, October 1995, pp. 28
-
32.

2.

Zoltán,

I., “Impedanz
synthese,” Technisches
Messen 68 (2001) 4, Oldenbourg Verlag,
Munich, Germany, pp. 179
-
181.

3.

Vargha, B. and I. Zoltán, “Calibration
Algorithm for Current
-
Output R
-
2R Ladders,”
IEEE Trans. on Instrumentation and
Measurement, Vol. 50, No. 5, October 2001, pp.

1216
-
1220.

4.

Szepessy, Zs. and I. Zoltán, “Thermal Dynamic
Model of Precision Wire
-
Wound Resistors,”
IEEE Trans. on Instrumentation and
Measurement, Vol. 51, No. 5, October 2002, pp.
930
-
934.


Biomedical Engineering Laboratory


Research interest:
electroni
c

biomedical
instr
u
ments, biosignal processing, marker
-
based
mov
e
ment anal
y
sis, home health monitoring.

www.mit.bme.hu/~jobbagy/biomed


Staff:

Ákos Jobbágy,
associate professor
, András
Görgényi,
senior lecturers,

Károly Bretz jr.,
PhD
student
.

Education:
B
iomedical Instrumentation
,
Ele
c
tronic
Measuring Equipment, Project Laboratory and
Thesis work for Biomedical Instrumentation.

Resources and infrastructure:
passive marker
-
based motion analysers: PRIMAS (precision 3D)
and PAM (simple 2D), electronic biomedi
cal
i
n
struments: (ECG, PPG, blood
-
pressure monitors,
pulmonary analyser), battery operated (scope
m
e
ters, hand
-
held DMMs) and bench
-
top electrical
instruments.

Major research and development projects:

Movement analysis
: “Development of signal
proces
s
ing a
lgorithms to compensate the non
-
ideal
proje
c
tion of passive marker
-
based motion
analysers,” financed by NWO and OTKA. (See:
www.mit.bme.hu/

~jobbagy/parkinson/parkinson.htm
,

~jobbagy/cdreklam/Markerbasedma.html
)

Diagnosis and staging of patients with neura
l
di
s
eases is challenging, especially in the early phase.
Passive marker
-
based motion analysis helps the
o
b
jective assessment providing information about
the mov
e
ment of body segments during well
-
defined
hand
-

and finger movements.

We developed different
feature extraction met
h
ods
to evaluate the movement and thus the actual
pe
r
formance of the tested persons. These tests help
in the early diagnosis of Parkinson's disease as well
as in setting the appropriate medication of patients.
Our tests confirmed that

Parkinson's disease
man
i
fests itself uniquely in the movement disorders
of a patient.
A simple and cheap image
-
based
motion analyser (PAM) has been developed at the
Depar
t
ment that is affordable for routine clinical
use.

We offer also the programs that ev
aluate the
perfor
m
ance of tested persons, taking into account
the reg
u
larity and the speed of the movements.

Partners:

E. Hans Furnée, TU Delft, Péter Ha
r
cos,
Szt. Imre Hospital, Emil Monos, Semmelweis
Un
i
versity, Gábor Fazekas, Szt. János Hospital,
OORI.





Figure 5.
Marker trajectories during the finger
-
tapping test. Performance of the right and left hand
of a healthy subject (above) and a newly diagnosed
Parkinsonian (b
e
low).


Home health monitoring: “
Artificial patient and
model in medical informatics,” financed by FKFP,
and “Home health monitoring,”

f
i
nanced by OTKA.

World life expectancy more than doubled over the
past two centuries, a further increase is est
i
mated.
N
ational health care systems should be
a
c
commodated; the prevalence rates of many
diseases substantially change over age. The average
medical expenditure per person is significantly
higher for the elderly than for younger people.

Keeping the healthiness of
the population can be
helped by home health monitoring. Many diseases
can be treated more effectively and at a lower cost if
early signs are detected.

In Hungary cardiovascular diseases are the lea
d
ing
cause of death, being responsible for about half of
t
he deaths [www.bel2.sote.hu/hipertonia]. It is
estimated that 30% of the Hungarian population has
hypertonia, above age 65 this ratio increases to
a
p
proximately 65%. Diagnosis in the early stage
would make it possible to start medication and
treatment to p
revent the deterioration of the patients.

The presently existing blood
-
pressure meters e
i
ther
require trained operator or do not assure acc
u
rate


measurement. Automatic and semi
-
automatic blood
-
pressure meters are simple
-
to
-
use thus wid
e
spread in
home healt
h monitoring. However, their results are
not accurate and reproducible enough, the reliability
of self
-
assessment is not satisfactory, medical
doctors have reservations for the results. The best
grade (A) in the British Hypertension Soc
i
ety
standard allows

40% of the results deviate from the
reference by more than 5 Hgmm, 15% of the results
by more than 10 Hgmm and 5% of the r
e
sults by
more than 15 Hgmm. The aim of our r
e
search work
has been
to increase the accuracy and
reproducibility of the indirect, cuf
f
-
based blood
pressure measurement
with the help of the
ph
o
toplethys
mographic (PPG) signal. A method has
been developed to measure the systolic and diastolic
pressure and not the mean pressure as it is done
while using the oscillo
metric method. A patient

monitoring device is being developed that is able to
store daily physi
o
logical measurement results (blood
pressure, 10
-
s ECG recording) for 2 months. The
device is also able to analyse the recorded data and
request help if needed via mobile phone.

Partner
s:

Gábor Halász (
BUTE, Faculty of
Mechanical Eng.
), Márk Kollai (Semmelweis
Un
i
versity).

Contact person:

Ákos Jobbágy

jobbagy@mit.bme.hu

www.mit.bme.hu/~jobbagy/




Selected publications:

1.

Jobbágy, Á., L. Gyöngy, E. Monos,

Quantitative evaluation of long
-
term locomotor
activity of rats,”

IEEE Trans. on Instrumentation
and Mea
s
urement, Vol. 51, No. 2, Apr. 2002,
pp. 393
-
397.

2.

Jobbágy, Á, E.H. Furnée, P. Harcos, M. Tárczy
.,

“Early detection of Parkinson's disease through
automatic movement evaluation,” IEEE

Eng
i
neering in Medicine and Biology Magazine,
Vol. 17, No. 2, March
-
Apr. 1998, pp. 81
-
88.

3.

Jobbágy, Á, “Photoplethysmographic Signal
Aids Indirect Blood
-
Pressure Measurement
,

Proc. of MEDICON 2001, IX.


Mediterranean
Conf. on Medical and Biological Engin
eering
and Computing,

12
-
15 June 2001, Pula, Croatia,
pp. 262
-
264.

Computer Networks Laboratory

Research interest
: communication of embedded
systems, sensor networking, real
-
time and
distributed communications, quality of service,
wireless

networking.
htt
p://www.mit.bme.hu/projects/iiensor

Staff
:
Csaba Tóth,
senior lecturer
, Tamás
Kovácsházy
lecturer
, László Kádár and Balázs
Scherer
research assistants
.


Education
:
Multimedia Networking
,
Informatics
,
Project Laboratory

and
Thesis works

for Embedded
Systems
.

Resources and infrastructure
: two laboratories,
PC
-
based development systems for PIC (8 bit) and
ARM (32 bit) micro
-
controllers, a sample network
of voice over IP telephony (made by Siemens),
IEEE 802.11bg wireless network, Gigabit Ethernet
Cluster, 10/1
00Base
-
T networking components
including switches, routers, firewalls etc.

Major research and development projects:

Gigabit Ethernet Cluster:
Workpackage of NEXT
TTA


High Confidence Architecture for Distributed
Control Applications,

EU IST
-
2001
-
32111
Pro
gramme.
http://www.mit.bme.hu/projects/isensor/NEXT

The Gigabit workpackage explored the achievable
performance and the limitations and bottlenecks of a
TTA network composed of commercial off
-
the
-
shelf
high
-
end state
-
of
-
the
-
art hardware components. In
The
objective of NEXT TTA project was to develop,

Figure 6.
Network Laboratory I.

(NEXT TTA Gigabit Ethernet Cluster)

and implement novel algorithms, tools, and
components to provide a generic architecture for
safety
-
critical applications in different applic
ation
domains (e.g., aerospace, automotive, and railway
applications). NEXT TTA project was an integration
of many different problem solutions that have been
explored independently over many years in different
research institutions.

The Gigabit workpackage

explored the achievable
performance and the limitations and bottlenecks of a
TTA network composed of commercial off
-
the
-
shelf
high
-
end state
-
of
-
the
-
art hardware components. In
particular, the workpackage set
-
up a TTA cluster
consisting of ordinary PCs, wh
ich are the nodes of
the cluster, and a Gigabit Ethernet serving as the
interconnection network. All the components could
be purchased at the " next door computer shop".

Our workpackage implemented a Windows
-
based
host for this TTA cluster, and analysed t
he whole
system by measuring its performance and attributes.

Industrial application of modern info
-
communications technology

(IKTA

164/2000


Sponsored by the Hungarian Ministry of Education.)
Co
-
operation with VERTESZ Kft.

http://www.mit.bme.hu/projects/is
ensor/IKTA2000

During the last five years a remarkable spreading of
high
-
level communication technologies, principally
the Ethernet and internet, was noticeable in the
embedded system market. As a result, most of the
leading embedded system manufacturers h
ave
started offering solutions to connect their devices
into TCP/IP protocol based computer networks,
unfortunately, using non
-
standard protocols in the
a
p
plication layer.

The goal of this project was to review the applicable
internet protocols and system
architectures, to
describe a solution for developing network capable
smart sensors and actuators, with good system
int
e
gration ability.












Figure 7.
Network Laboratory II.

http://rten.mit.bme.hu/projects/isensor/ICCC2003

We have developed an SNMP
-
based pseudo NCAP
(based on IEEE 1451) providing a transducer
independent network accessible interface, useable to
formalise the control of devices with different
functions.
http://rten.mit.bme.hu/projects/isensor/IMTC2003

Contact person:


Csaba Tóth


tot
h@mit.bme.hu

http://www.mit.bme.hu/~toth/




Selected publications:


1.

Cs. Tóth, B. Scherer, L. Kádár, T. Bakó:
Implementation possibilities of networked smart
transducers, ICCC 2003, International
Carpathian Control Conference, Tatranska
Lomnica, Slovak Rep
ublic, 26
-
29 May 2003,
pp. 198
-
201.

2.

B. Scherer, Cs. Tóth, T. Kovácsházy., B.
Vargha: SNMP
-
Based Approach to Scalable
Smart Transducer Networks, IMTC 2003, IEEE
Instrumentation and Measurement Technology
Conference, Vail, Colorado, USA, 20
-
22 May
2003, pp.

721
-
725.

3.

Tamás Kovácsházy, Róbert Szabó, Performance
Measurement Tool for Packet Forwarding
Devices, 2001 IEEE Instrumentation and
Measurement Technology Conference IMTC
2001, Budapest, Hungary, 2001, Vol. 2., pp.
860
-
863,

4.

T. Péter, Cs. Tóth, Quality of S
ystem
Monitoring in a Complex Internet Service
Provider
-

Case study. IEEE International
Conference on Intelligent Engineering Systems
(INES’99), Slovakia, Nov. 1
-
3, 1999, pp. 629
-
633.

Logic Design Laboratory

Research interest:

digital system design, high
level
synthesis, advanced signal and image proces
s
ing
architectures, embedded microprocessor sy
s
tems,
dynamically reconfigurable computers, and system
on a pr
o
grammable chip implementations.

Staff:
Béla Fehér
,

Gábor Horváth,
associate
professors
, Lőrinc An
toni,
research assistant,
Péter
Szántó
PhD student
.


Education:

The laboratory has a central role in the
practical education of the students of the Embedded
Systems Branch. Our open laboratory policy makes



the lab to a familiar working place not only for t
he
cu
r
ricula lectures, but also for the elaboration of the
particular student ideas as well. Subjects related to
the lab
o
ratory are
Digital Technique, Logic Design,
Microprocessor Systems, Design of SoPCs by
FPGAs, student project and thesis works.

Resour
ces and infrastructure:
The laboratory is
equipped with 12 PCs, configured as W2000
wor
k
stations. All important design software’s are
avai
l
able in the laboratory, including the Xilinx ISE
and EDK FPGA development system, the Matlab
Env
i
ronment, the Mentor
Graphics ModelSim,
FPGA Advantage, SystemVision, Seamless and
Celoxica Handel
-
C tools. Te
k
tronix TPA 700 LA or
ARM MultiICE IDE development boards from
Digilent and XESS are also available.

Major research and development projects:
The
Logic Design labora
tory is the centre of the
d
e
par
t
ment’s research work for the design of
complex digital systems, with emphasis on the
application of FPGAs and exploitation of the re
-

configurability. Significant results were achieved
with the application of FPGAs in the fi
eld of digital
signal processing. Different basic li
n
ear FIR and IIR
filter structures, DSP core gener
a
tors, and efficient
finite word and distributed arithmetic building
blocks were developed [1]. Based on sp
e
cial
recursive algorithm, high performance 1D
and 2D
linear transform modules (WHT, DCT) were
implemented in an area optimized way [2]. Similar
methods were used later to impl
e
ment nonlinear
median filters as well, for high speed video signal
processing. Current research is focused on FPGA
implementat
ion of advanced 3D rendering
alg
o
rithms for portable applications with
reconfigurable computing architectures [3].

Figure 8.
48 tap, 16 bit FIR filter in a 5k gates
FPGA



Figure 9.
LOGSYS
-
BLOXES FPGA Educational
Board

Significant work has been done to

offer a modular
FPGA/PLD development board family for the
st
u
dents, called LOGSYS
-
BLOXES. Three levels of
boards has been made, supporting the different
needs of the ed
u
cation in the basic, entry level logic
design, and later on the i
m
plementation of more

complex DSP and commun
i
cation units and system
on a chip development and verification. A simple,
standardized USB
-
based d
e
bugger, control and
power interface is also provided with a rich set of
interesting peripheral interface modules.

Unique property o
f dynamic reconfiguration (DRC)
capability of some SRAM technology based FPGAs
makes possible very special applications, for
exa
m
ple the dependability and fault tolerance
analyses of complex digital systems. DRC is used to
inject Si
n
gle Event Upset (SEU) o
r stuck
-
at
-
1 (or 0)
like e
r
rors into the logic and evaluate the behaviour
in real time [4]. This research was done in
cooperation with Prof. Régis Leveugle, TIMA,
France. Efficient arithmetic modules were also
developed exploiting the DRC, in frame of the
national FKFP project Re
-
configurable Computing
Architectures (0413/1997). Partners were University
of Ves
z
prém and University of Miskolc. The Logic
Design Laboratory also serves as a Tec
h
nology
Expertise Center (TEC) in different national and EC
projects.

It offers consultation
and design services for SMEs
interested in a
d
vanced
embedded system design
methodologies. The EC funded
FP5 technology transfer project JENET (Joint
European Network of Embedded Internet
Technologies, IST IST
-
2000
-
28422) is a good
e
xample of these acti
v
ity. JENET is promoting the
use of the new comm
u
nication capabilities in
industrial applications, specifically the embedded

Figure 10.
JENET presentation,

Magyar Regula, 2003.

internet technology in pro
d
ucts and systems
developed by E
uropean ente
r
prises. JENETis carried
out by a network of 7 TECs and 27 User Companies
(UCs) from Belgium, Ge
r
many, Hungary, Italy,
P
o
land, Romania and United Kingdom. Local
partner SMEs are Infoware Co., Meldetechnik Ltd.,
Silex Ltd., and the project coo
r
d
inator is CRR, Italy.
More info
r
mation:
http://www.eurojenet.com
.

Contact Person:

Béla Fehér

feher@mit.bme.hu

http://www.mit.bme.hu/~feher/





Selected publications:

1.

Fehér, B., “Efficient Synthesis of Distributed
Vector Multipliers,” Journal of Microp
rocessors
and Microprogramming, Vol. 38. No. 1
-
5. 1993
.

2.

Fehér, B., “ New Inner Product Algorithm of the
2D DCT,” Digital Video Compression:
Algorithm and Technologies, Proc. SPIE, Vol.
2419. ISBN 0
-
8194
-
1766
-
1.

3.

Szantó, P. and B. Fehér, “3D Rendering usin
g
FP
G
As,” IFIP International Conference on
VLSI SOC, December 1
-
3, 2003 Darmstadt,
G
ermany.

4.

Antoni, L., R. Leveugle, B. Fehér, “Using run
-
time reconfiguration for fault injection
applications,” IEEE Trans. on Instrumentation
and Measurement, Vol. 52, No. 5
, October 2003.





Digital Signal Processing Laboratory

Research interest:

Signal modelling, adaptive
signal processing, digital filter structures, transform
-
domain signal processing. Signal processing in
complex measurement systems.

Staff:

László Sujber
t, László Naszádos
senior
lecturers
, Balázs Bank,
research assistant
, Károly
Mo
l
nár
PhD. student
. Part
-
time contributors: Gábor
P
é
celi,
professor
, Tamás Dabóczi,
associate
professor
, Gyula Simon,
senior lecturer
.


Education:

Embedded systems laboratory,
In
fo
r
mation systems laboratory, Project laboratory.

Resources and infrastructure:



DSP development boards (Analog Devices,
Motorola, Texas Instruments)



Vibro
-
acoustic transducers, signal
conditio
n
ers (Brüel&Kjaer)



Digital storage scopes, spectrum analyzers,
s
pecial generators (LeCroy, HP)

Major research and development projects:

Active noise control

is an old idea for acoustic
noise suppression, but it could be implemented only
since the advent of digital signal proce
s
sors. The
solution is based on the destruc
tive inte
r
ference
ph
e
nomenon. We have developed a dedicated
method for suppressing periodic noise components.
The method is the extension of the resonator
-
based
observer developed also at the department. The
advantages of the res
o
nator
-
based noise controll
er
are its fast convergence (compared to other
methods) and its low comput
a
tional burden. Based
on the experiences with the resonator
-
based periodic

noise contro
l
ler, we have developed a modification
of the well
-
known filtered
-
X LMS algorithm

Figure 11.
Ty
pical performance of an active noise
control system

allowing faster conve
r
gence for broadband noise
control, as well. Grants, intern
a
tional relations:



OTKA: Acoustic applications of digital
signal processing, F 035060



TPD
-
TNO Delft, the Netherlands
http://www.tpd.tno.nl

Digital sound synthesis

of musical instruments has
been acclaimed at the department in the last years. It
needs very precise measurements and poses serious
signal proces
s
ing problems. The results achiev
ed in
this field can be utilized generally, e.g. in system
ident
i
fication or in filter design. We have
successfully synthesized the sound of organ, violin
and piano. Most of research results were achieved
for piano sound synthesis, where the digital
wavegu
ide model has been improved. Grants,
international relations:



OTKA: Acoustic applications of digital signal
processing, F 035060



MOSART IHP (Improving Human Potential)
Training Network, HPRN
-
CT
-
2000
-
00115
http://www.diku.dk/forskning/musinf/mosart



Helsinki

University of Technology, Laboratory
of Acoustics and Audio Signal Processing
http://www.acoustics.hut.fi



University of Padua, Department of Inform
a
tion
Engineering
http://www.dei.unipd.it

One of our latest industrial projects is
develo
p
ment
of a DSP
-
base
d system for in
-
motion weighing of
rai
l
way carriages.

It is a two
-
level system that
comprises of 16 or 24 DSP
-
based Measurement
Units (MU) and a powerful HOST PC. The MUs
store the deformation signals of the rail caused by



Figure 12.
Transfer function m
easurement of a
violin body

the wheels of an in
-
motion train. The deformation is
measured by strain gauges. AD co
n
verters sample
the signal of the strain gauge bridge, and this signal
is processed at the DSP. The HOST collects the
stored data, and a large
database is built for each
train.

Contact person:

László Sujbert

sujbert@mit.bme.hu

www.mit
-
bme/~sujbert/




Selected publications:

1.

Sujbert, L., and G. Péceli, “Signal model based
per
i
odic noise controller design,”
Measurement
-

the Journal of the IMEKO,

vol. 20, No. 2, pp.
135
-
141.

2.

L. Sujbert, “A new filtered LMS algorithm for
active noise control,” Proc. of the Active '99
-

The International EAA Symposium on Active
Control of Sound and Vibration, Dec. 2
-
4, 1999,
Fort Laude
r
dale, Florida, USA, pp. 1101
-
1
110.

3.

Bank, B., and Vesa Välimäki, "Lobust Loss
Filter Design for Digital Waveguide Synthesis
of String Tones,"
IEEE Signal Processing
Letters,
vol. 10, No. 1, pp. 18
-
20, Jan. 2003.


Chaotic Signals and Systems
Laboratory

Research interest:

Chaotic communic
ation
sy
s
tems, analysis and computer simulation of data
communic
a
tion systems, frequency synthesis, phase
-
locked loop.
http://www.mit.bme.hu/research/chaos/

Staff:
Géza Kolumbán,
associate professor
, Gábor
Kis, Zoltán Jákó,
research assistants,

Zoltán Szab
ó,
Béla Frigyik,
PhD students
.

Education:
Electronics I and II, Theory and
Appl
i
cations of Nonlinear Theory and Chaos (PhD
course), Sy
s
tem Level Design and Analysis. Project
Laboratory works and MS Theses.

Resources and infrastructure:

Linux
-
based PCs.

Maj
or research and development projects:

Development and analysis of novel signal
proces
s
ing architectures for system
-
on
-
a
-
chip
(SoC) int
e
grated circuits
,

T038083, financed by
OTKA (2002
-
2005).

The project has been launched to find new
tran
s
ceiver and frequen
cy synthesizer configurations
for co
m
munication and measurement purposes.

Partners:

Prof. G.

Chen (City University of Hong
Kong; Profs. C.M.

Lau and C.K.

Tse, The Hong
Kong Polytechnic University.

Innovative signal processing exploiting chaotic
dynamics (I
NSPECT),

Esprit Project 31103, Open
LTR


2
nd

phase, Financed by European
Commi
s
sion, 1998
-
2001.

http://www.cordis.lu/esprit/src/31103.htm,
http://www.mit.bme.hu/research/chaos/inspect/

Chaotic signals are inherently wideband signals that
can be generated

with high power efficiency using
simple nonlinear circuits in any frequency band and
at arbitrary power level. In chaotic co
m
munications,
the digital information to be transmi
t
ted is mapped
directly into a wideband chaotic waveform. Chaotic
comm
u
nication
offers a low cost alternative solution
to conventional spread spectrum communication.

Seven European universities collaborated in the
INSPECT Esprit Project to find applications for
chaotic signals in communication and watermarking
of digital pictures. The

Chaotic Systems Team
coo
r
dinated the research and implementation of a
wor
k
ing prototype of frequency
-
modulated chaos
-
shift keying (FM
-
DCSK) communication system.
We have invented FM
-
DCSK (the most robust
chaotic modulation scheme), derived exact
expressio
ns for the noise performance of correlator
-
based chaotic modulation schemes, developed an
ultra fast co
m
puter simulator to evaluate the system
performance of digital communication systems
under various channel conditions, elaborated the
system proposal and

determined the system level
param
e
ters for the INSPECT FM
-
DCSK chaotic
data communications system.

The INSPECT FM
-
DCSK radio shown in Fig

13
operates in the 2.4
-
GHz ISM band and was
succes
s
fully tested in 2001. To illustrate its excellent
mult
i
path perfor
mance, the bit error rate (BER)
curves of conve
n
tional differential phase
-
shift
keying (DPSK) and chaotic FM
-
DCSK are
compared in Fig.

14. A
l
though the single
-
ray
performance of FM
-
DCSK is worse than that of
DPSK, in the indoor multi
-
path channels the DPSK

fails completely (see dash
-
dotted curve) while FM
-
DCSK has only a 4
-
dB loss in the system
perfor
m
ance (see dashed and dotted curves).

Our direct partner in the INSPECT Project was Prof.
M.P.

Kennedy, University College Dublin.

Spread spectrum communicatio
n exploiting
chaos
, Office of Naval Research (ONR), USA,
1995
-
1996.

Figure 14
. BER curves of conventional DPSK and
ch
a
otic FM
-
DCSK in a single
-
ray additive white
Gau
s
sian noise (AWGN) channel (solid and dashed,
r
e
spectively) and in an indoor multi
-
path ch
annel
(dash
-
dotted and dotted, respectively.

The goal of this project was to propose an
u
n
derwater chaotic communication scheme for the
submarines of US Navy. In the project we have
elaborated a comprehensive theory for chaotic
wav
e
form communic
a
tions.

Par
tners:

Prof. L.O.

Chua, University of California,
Berkeley, and Prof. M.P.

Kennedy, University
Co
l
lege Dublin.

Contact person:


Géza Kolumbán,

kolumban@mit.bme.hu

www.mit.bme.hu/~kolumban/





Selected publications:

1.

Kolumbán, G., M.P. Ke
n
nedy, Z. Jákó

and G.
Kis, “Chaotic communications with correlator
receiver: Theory and performance limits,”
i
n
vited paper in Proceedings of the IEEE, vol.
90, pp. 711
-
732, May 2002.

2.

Kennedy M.P., and G. Kolumbán, guest ed
i
tors,
Special Issue on “Noncoherent Chaotic
Communic
a
tions,” IEEE Trans. Circuits and
Syst. I, vol. 47, pp. 1661
-
1732, December 2000.

3.

Kolumbán, G., M.P. Kennedy and L.O.

Chua,
“The role of synchronization in digital
co
m
munications using chaos,” IEEE Trans.
Ci
r
cuits and Syst. I, Part

I: “Fundament
als of
digital communications,” 44(10): 927
-
936,
October 1997; Part

II: “Chaotic modulation and
chaotic synchronization,” 45(11): 1129
-
1140,
November 1998; Part

III: “Performance
bounds,” 47(12): 1673
-
1683, December 2000.

4.

G. Kolumbán, “Theoretical noise

performance
of correlator
-
based chaotic communications
schemes,” IEEE Trans. Circuits and Syst. I, vol.
47, pp. 1702
-
1711, December 2000.

5.

G. Kolumbán, “The theory and implement
a
tion
of a robust chaotic digital communic
a
tions

system,” invited talk at
2003 Microwave
Symposium Workshop, IEEE International
Microwave Symposium, Philadelphia, USA,
June 2003.

www.ims2003.org/technical/workshop/
WMA.htm


Figure 13.

Picture of the 2.4
-
GHz FM
-
DCSK prototype receiver built in the framework of INSPECT Espri
t
Pr
o
ject.


System Identification Laboratory

Research interest:

identification of linear systems,
p
a
rameter estimation, SISO/MIMO modelling,
effect of nonlinear disturbances, signal reconstruct
-
tion u
s
ing known measurement system models
(inverse filte
r
ing
).

Staff:

István Kollár,
professor
, Tamás Dabóczi,
a
s
sociate professor
, Gyula Simon,
senior lecturer
,
József Németh,
research assistant
, László Balogh,
János Márkus, Balázs Vödrös,
PhD students
, Zoltán
Bilau,
graduate student
.

Education:

Digital signal pro
cessing, System
ident
i
fication, Embedded systems, Project
Laboratory, and Diploma thesis design.

Major research and development projects:

Identification in the Frequency Domain

The close cooperation between our department, and
the Department ELEC at the V
rije Universiteit
Bru
s
sel, Belgium (
http://wwwtw.vub.ac.be/elec/
), is
co
n
tinuous since 1989. One of the major results of
this cooperation is the Frequency Domain System
Ident
i
fication Toolbox for MATLAB. The
peculiarity of the frequency domain methods is t
hat
they solve the maximum likelihood equations in the
frequency d
o
main, making it possible to fully
exploit the adva
n
tages of harmonic e
x
citations.

An important step in identification is the validation
of the results. We always have to check whether the
r
esult really satisfies our requirements, is in no
co
n
tradiction with the preliminary assumptions, and
co
r
responds to the data. A program can only offer
tools for this purpose: the validation itself is the task
of the person who performs the identification.


The toolbox effectively uses the following advanced
MATLAB tools:



graphical user interface,



automatic procedures, and



data structures.

The investigated system can be anything from
ele
c
trical systems (filters, machines) to mechanical
sy
s
tems (airplanes, c
ars, robot arm) and acoustical
sy
s
tems (airplane cabin, loudspeaker), etc.

The toolbox is now in use throughout the world.
Linear modelling is currently being extended to
cha
r
acterize slight nonlinear distortions, and to
model multiple input


multiple out
put systems.

Inverse filtering

The accuracy of time domain waveform
measur
e
ments is limited by the finite bandwidth of
the measurement instrument. This means that high
fr
e
quency components of the signal will be
suppressed and the phase of the different fre
quency
components will be modified. The result is a



Figure 15.
Compare and Evaluate Models
window of the GUI of the fdident toolbox

distorted waveform; the fast changes of the signal
are rounded, rapid transitions are stretched out.
Digital post
-
process
ing of the measured data can
improve the result. This is called inverse filtering.
This problem is usually ill
-
posed, that is, small
changes in the measured output signal cause large
fluctuations in the estimation of the input signal.

Different inverse fil
tering techniques provide
diffe
r
ent approaches to suppress the amplified noise
wit
h
out significantly distorting the useful signal.

Successful applications of inver
se filtering:



High voltage lightning measurements:
co
m
pensating the distortion of high volta
ge
divi
d
ers. Cooperating party: Swiss Federal
Institute of Technology, Zürich, Switzerland,
High Voltage Laboratory



Calibration of ultra high
-
speed oscilloscopes.
Cooperating party: National Institute of
Sta
n
dards and Technology, NIST, USA



Restoration the
sound of old movies, kept on
film


Figure 16.
Measured and reconstructed high voltage
lightning i
m
pulses


Figure 16.
High voltage lightning impulse
measurement setup

High voltage generator, chopping gap and high
voltage dividers


HV laboratory of the ET
H Zürich

Recent Research Grants:

OTKA (Hungarian Scientific Research Fund), NIST
(National Institute of Standards and Technology,
USA), Hungarian Ministry of Education.

Contact persons:






István Kollár

Tamás Dabóczi


kollar@mit.bme.hu

daboczi@mit.bme
.hu


www.mit.bme.hu/~kollar/

.../~daboczi/

Selected publications:

1.

FDIDENT (1999
-
2003), Frequency Domain
System Identification Toolbox Developers’
Page.
http://elec.vub.ac.be/fdident/

2.

Kollár, I., R. Pintelon, Y. Rolain, J. Schoukens,
and Gy. Simon, “F
requency Domain System
Identification Toolbox For MATLAB:
Automatic Processing


From Data To Models.”
IFAC Symposium on System Identification,
SYSID 2003, Aug. 2003, Rotterdam.

3.

Dabóczi, T., I. Kollár, Gy. Simon, and T.
M
e
gyeri, “How to Test Graphical User

Interfaces?” IEEE Instrumentation and
Measurement Mag
a
zine, Vol. 6, No. 3, pp. 27
-
33, Sep. 2003.

4.

Deyst, J. P., N. G. Paulter, T. Dabóczi, G. N.
Stenbacken, T. M. Souders, "A Fast Pulse
Osci
l
loscope Calibration System," IEEE Trans.
on I
n
strumentation and M
easurement, Vol.

47,
No.

5, pp.

1037
-
1041, 1998.