| 1. |
- Bengtsson, Lars, 1963
(author)
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Mikrodatorteknik
- 1995
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Book (other academic/artistic)abstract
- Första delen behandlar Microchips "Base-line"-kretsar och andra delen behandlar "Midrange"-kretsarna. De flesta funktioner belyses med konstruktionsexempel. Exempel och övningar är mycket hårdvarunära och boken behandlar konstruktion av mikrodatorer från grunden. Boken är avsedd för kurser i mikrodatorteknik på högskolan eller annan högre teknisk utbildning, men kan även användas som självstudiematerial eftersom de flesta exempel ges med detaljerade och verifierade lösningar av såväl hård- som mjukvaran. Tidigare erfarenhet av assemblerprogrammering är inte nödvändig men grundläggande kunskaper i digitalteknik förutsätts. Boken kan med fördel också läsas av rutinerade assemblerprogrammerare som vill veta hur prestanda hos de nya RISC-baserade PIC-controllerna står sig i konkurrensen med de mer etablerade enchipscontrollerna, t ex HC11 och 8751, som bygger på traditionell CISC-arkitektur.
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| 2. |
- Bengtsson, Lars, 1963
(author)
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RISC-baserad 50 MHz räknare med alfanumerisk display
- 1995
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In: Allt om elektronik. ; 6, s. 35-37
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Journal article (other academic/artistic)abstract
- Denna artikel presenterar en konstruktion som använder en RISC-kontroller (PIC16C54) som frekvensräknare. Frekvensen räknas på controllerns RTCC-ingång och signalfrekvensen, uttryckt i kHz visas på en alfanumerisk display.
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| 3. |
- Bengtsson, Lars, 1963
(author)
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Generation and measurement of pulses and delays with RISC-controllers
- 1997
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In: Measurement Science and Technology. - : IOP Publishing. - 0957-0233 .- 1361-6501. ; 8, s. 679-683
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Journal article (peer-reviewed)abstract
- An instrument for the generation of pulses and delays has beendeveloped for applications in laserspectroscopy experiments. The pulses from achopped laserbeam are counted, and when a preset value is reached, two signalsare generated: one delayed trigger pulse with constant length and one delayed‘shutter pulse’ (referred to as the ‘shutter window’ below) which opens a light shutterand allows one light pulse to enter the experimental region and excite the sample.The delays of the trigger pulse and the shutter window and the width of the shutterwindow can all be set independently to any value from 0 up to 50 ms with 0.05 mssteps. A separate microcontroller measures the width of the shutter window with anaccuracy of 1micro seconds. The pulse delays and the width of the shutter window are setwith thumbwheel potentiometers connected as voltage dividers. A microcontrollerreads the set values with a four-channel, 12-bit AD converter. This techniquesaves a lot of hardware wiring as well as software writing when compared to thealternative of using separate, BCD-coded thumbwheels for each timesetting.In total, the instrument consists of two independent RISC-controllers: onePIC16C55 for counting chopper pulses and generating pulses and delays, and onePIC16C74 for measuring (and displaying) the width of the shutter window. Thewidth of the shutter window is measured with 1micro second resolution by taking fulladvantage of two different peripherial I/O devices in the PIC16C74: the 16-bit ‘inputcapture’ module and the external interrupt facility.
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| 4. |
- Nilsson, Peter, et al.
(author)
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A bit-serial realization of a lattice wave digital intermediate frequency filter
- 1993
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In: Proc. Sixth Annual IEEE Int. ASIC Conf. and Exhibit, ASIC'93. - 0780313755 ; , s. 197-200
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Conference paper (peer-reviewed)abstract
- A custom DSP chip for mobile radio systems like the American IS-54 system is presented. The application is a digital intermediate frequency filter which is intended to replace expensive analog filters. It is a lattice wave digital filter with fixed coefficient bit-serial arithmetic. A technique which is useful for area efficient layouts in high throughput real time signal processing is discussed.
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| 5. |
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| 6. |
- Nilsson, Peter, et al.
(author)
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CMOS on-chip clock for digital signal processors
- 1993
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In: Electronics Letters. - Stevenage, UK : IET. - 0013-5194 .- 1350-911X. ; 15:8, s. 669-670
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Journal article (peer-reviewed)abstract
- An on-chip clock for frequencies up to 190 MHz is presented. This clock generator can be used for application specific digital signal processors which are clocked faster than the off-chip system clock. It is useful for both processors with a few cycles per sample or for high frequency bit-serial processors which need a large number of cycles.
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| 7. |
- Ujvari, Sandor, 1972-, et al.
(author)
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Simulation and emulation of sensor systems for intelligent vehicles
- 1998
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In: Mechatronics '98. - : Pergamon Press. - 0080433391 ; , s. 385-390
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Conference paper (peer-reviewed)abstract
- Simulation of sensor systems for mobile robots are described in this paper. By simulation of smart sensor systems, the performance of semi-autonomous vehicles / mobile robots can be enhanced. Smart sensor systems used in the field of mobile robotics can utilise adaptive algorithms. e. g. artificial neural nets, fuzzy logic or hybrid variants of these systems. The development, training and evaluation of adaptive algorithms for sensor systems can be done within a virtual environment in which graphical models are built to simulate an intelligent vehicle, its sensors, and its environment. The virtual sensors are validated by comparing the characteristics of the virtual sensors with those of the real devices.
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| 8. |
- Viberg, Mats, 1961, et al.
(author)
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Maximum Likelihood Array Processing in Spatially Correlated Noise Fields Using Parameterized Signals
- 1997
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In: IEEE Transactions on Signal Processing. - : Institute of Electrical and Electronics Engineers (IEEE). - 1941-0476 .- 1053-587X. ; 45, s. 996-1004
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Journal article (peer-reviewed)abstract
- This paper deals with the problem of estimating signal parameters using an array of sensors. This problem is of interest in a variety of applications, such as radar and sonar source localization. A vast number of estimation techniques have been proposed in the literature during the past two decades. Most of these can deliver consistent estimates only if the covariance matrix of the background noise is known. In many applications, the aforementioned assumption is unrealistic. Recently, a number of contributions have addressed the problem of signal parameter estimation in unknown noise environments based on various assumptions on the noise. Herein, a different approach is taken. We assume instead that the signals are partially known. The received signals are modeled as linear combinations of certain known basis functions. The exact maximum likelihood (ML) estimator for the problem at hand is derived, as well as a computationally more attractive approximation. The Cramer Rao lower bound (CRB) on the estimation error variance is also derived and found to coincide with the CRB, assuming an arbitrary deterministic model and known noise covariance.
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| 9. |
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| 10. |
- Sobral, L., et al.
(author)
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Ultrasonic Detection in Robotic Environments
- 1996
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In: Proceedings., 1996 IEEE International Conference on Robotics and Automation. - 0780329880 ; 1, s. 347-352
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Conference paper (peer-reviewed)abstract
- Based on information produced by a 200 kHz ultrasonic echo device developed for robotics and other industrial purposes, a method for object identification was developed and is presented in this paper. Interpretation of the echos from the reflecting objects, complexity analysis and information extraction were made by system identification methods such as impulse response analysis and state-space realization. A clustering-type discrimination of different objects based on the echo identification result was made in a subsequent step using the least-squares method. Experimental evaluation showed that the method is effective for object recognition
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| 11. |
- Wiklund, Magnus
(author)
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Electrothermal Simulation in a Concurrent Waveform Relaxation Based Circuit Simulator
- 1998
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Doctoral thesis (other academic/artistic)abstract
- The main purpose of this work is to study methods to simulate electro-thermal effects in integrated circuits using CONCISE a waveform relaxation based circuit simulator. WR is a method that is suitable to run on a multi-computer with state of the art computing power. Especially CMOS VLSI circuits have been simulated successfully with WR. With simulation experiments we have shown that it is possible to use WR methods to simulate the electro-thermal couplings that are present in integrated circuits. The approach we have used for modeling the electro-thermal couplings is general and can be used in standard circuit simulators, such as SPICE. One contribution is the augmented transistor modeling approach. The idea is to have an augmented transistor model that adds thermal behavior to the built-in transistor model. This is especially useful in the design of electronic circuits when we consider dynamic thermal effects using existing transistor models which typically only consider the temperature as a constant parameter. The augmented transistor model enables the user to model both the thermal network and its dynamic couplings to the electrical network. Principles of thermal network modeling are also presented to help the reader understand the couplings between the electrical and the thermal domains. Physical thermal relations are transformed into electrical analogies suitable for simulation by a circuit simulator. The result is an approach intended for modeling of multidimensional thermal networks. For the synthesis of compact models of the multidimensional thermal network we have found it practical to use bond graphs to illustrate the derivation steps. Another purpose of this work is to simplify the task of writing functional models in CONCISE; our in-house circuit simulator. The proposed method of incorporating functional elements into a bond graph relies on an analogy between the numerical solver and the circuit primitive norator. We have extended the bond graph language with nullator and norator elements, which are frequently used in circuit theory. With these new bond graph primitives we have shown that it is possible to start with a design equation and synthesize an electrical circuit. We have specifically investigated the synthesis of a translinear circuit.
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| 12. |
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| 13. |
- Eriksson, Patric, et al.
(author)
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A role for 'sensor simulation' and 'pre-emptive learning' in computer aided robotics
- 1995
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In: 26th International Symposium on Industrial Robots, Symposium Proceedings. - : Mechanical Engineering Publ.. - 1860580009 ; , s. 135-140
-
Conference paper (peer-reviewed)abstract
- Sensor simulation in Computer Aided Robotics (CAR) can enhance the capabilities of such systems to enable off-line generation of programmes for sensor driven robots. However, such sensor simulation is not commonly supported in current computer aided robotic environments. A generic sensor object model for the simulation of sensors in graphical environments is described in this paper. Such a model can be used to simulate a variety of sensors, for example photoelectric, proximity and ultrasonic sensors. Tests results presented here show that this generic sensor model can be customised to emulate the characteristics of the real sensors. The preliminary findings from the first off-line trained mobile robot are presented. The results indicate that sensor simulation within CARs can be used to train robots to adapt to changing environments.
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| 14. |
- Anders, Berntson, et al.
(author)
-
Self-phase modulation in dispersion compensated optical fibre transmission systems
- 1996
-
In: Optics Communications. - : Elsevier. - 0030-4018 .- 1873-0310. ; 130:1-3, s. 153-162
-
Journal article (peer-reviewed)abstract
- An analysis is made of the influence of self-phase modulation on optical fibre communication systems where the chromatic dispersion is compensated for by a dispersion compensation fibre. In particular we derive a simple and useful expression for the optimal fibre length in the presence of nonlinearities.
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| 15. |
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| 16. |
- Bakhshi, Bamdad, 1970, et al.
(author)
-
Measurement of the differential group delay in installed optical fibers using polarization multiplexed solitons
- 1999
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In: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 11:5, s. 593-595
-
Journal article (peer-reviewed)abstract
- We experimentally demonstrate a new technique for measurement of the differential group delay (DGD) in optical fibers using polarization-division multiplexed (PDM) solitons: the change in the separation of orthogonally polarized solitons propagating along different principal axes in a fiber equals the DGD at the signal wavelength. Based on this principle, we use PDM solitons to measure the accumulated DGD at different distances along a 400-km installed fiber. The measured DGD exhibits the expected square-root-of-length dependence, corresponding to a polarization-mode dispersion of 0.26 ps/km1/2. The results are in excellent agreement with those obtained by a commercial instrument utilizing Jones matrix eigenanalysis.
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| 17. |
- Bakhshi, Bamdad, 1970, et al.
(author)
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Soliton interaction penalty reduction by receiver filtering
- 1998
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In: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 10:7, s. 1042-1044
-
Journal article (peer-reviewed)abstract
- We present the first detailed numerical study of the impact of receiver low-pass filtering in soliton interaction-limited communication systems. We propagate 40-Gb/s pseudorandom bit sequences (PRBS's) of 28-1 solitons up to one soliton collision distance (Zc-) and optimize the filter bandwidth to minimize the interaction induced eye opening penalty. The distance at 0.5-dB penalty is increased over 40% through filtering. The penalty is essentially pulsewidth independent when considering distances normalized by Zc. We also show that PRBS's of at least 28 - 1 solitons are required to accurately simulate random data.
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| 18. |
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| 19. |
- Hedekvist, Per Olof E, 1967, et al.
(author)
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Polarization dependence and efficiency in a fiber four-wave mixing phase conjugator with orthogonal pump waves
- 1996
-
In: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 8:6, s. 776-778
-
Journal article (peer-reviewed)abstract
- We study the influence of pump separation on polarization dependence and on conversion efficiency in a fiberbased optical phase-conjugator with two orthogonal pump waves at different wavelengths. The polarization dependence is found to be minimized when the pump wavelength separation is small. Furthermore, both theory and experiments show that the efficiency is maximized if the signal wavelength is located close to one of the pumps.
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| 20. |
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| 21. |
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| 22. |
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| 23. |
- Höök, Anders, 1962, et al.
(author)
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Soliton instabilities and pulse compression in minimum dispersion fibers
- 1994
-
In: IEEE Journal of Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9197 .- 1558-1713. ; 30:8, s. 1831-1841
-
Journal article (peer-reviewed)abstract
- A new stability of ultrashort pulses in optical fibers is demonstrated which, together with a recently discovered modulation instability, is shown to deteriorate a pulse compression mechanism. The pulse compression is analyzed in detail by means of a perturbation technique.
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| 24. |
- Karlsson, Magnus, 1967, et al.
(author)
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Autocorrelation function of the polarization-mode dispersion vector
- 1999
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In: Optics Letters. - 0146-9592 .- 1539-4794. ; 24:14, s. 939-941
-
Journal article (peer-reviewed)abstract
- We derive, for what is believed to be the first time, the autocorrelation function (ACF) of the polarization-mode dispersion (PMD) vector, which gives information on the bandwidths of the principal states of polarization. We compare the ACF with measured data and find good agreement. Finally, we apply the derived ACF to calculate the average pulse broadening that is due to PMD.
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| 25. |
- Karlsson, Magnus, 1967
(author)
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Polarization mode dispersion induced pulse broadening in optical fibers
- 1998
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In: Optics Letters. - 0146-9592 .- 1539-4794. ; 23:9, s. 688-690
-
Journal article (peer-reviewed)abstract
- A simple and exact analytical expression is derived for the amount of broadening that a pulse suffers when it is subjected to the combined actions of polarization mode dispersion, chromatic dispersion, and chirping. The theory is then applied to various manifestations of second-order polarization mode dispersions.
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