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Professional Interests
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Here are my professional interests.
They overlap hobbies to some extent.
Digital ASIC design
Primarily interested in high speed digital logic design in Verilog
or VHDL (I prefer Verilog). If error correction code architecture
and implementation or implementation of any other applied theoretical
mathematics is involved, that is great, but I do general digital design
with emphasis on design quality, design for test, and reusability.
Digital logic and microcomputer hardware design
Digital and microcomputer hardware and firmware (assembly language) design is my
long time interest. Please, see my resume for
the list of projects I was involved in.
Completely Configurable Digital Transmitter
Project finished in the middle of August 1998. It is a mixed digital/analog/RF design.
Universal and highly configurable digital transmitter unit capable of generating almost
any I/Q modulation at up to 40Msamples/s with very flexible
and configurable pulse shaper, 60Ms/s when the pulse shaper is bypassed.
Built around Xilinx FPGA the transmitter can be configured for many data
transmitting and modulation tasks like multi-user CDMA transmitter, spread spectrum
jammer, and many others. More information is on a special
transmitter page.
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Get Away Special Space Shuttle Experiment
The details on hardware/software Space Shuttle project I was involved in
can be found on my Space Shuttle page.
The experiment, Single Event Upset high density static RAM radiation experiment,
was designed to test how high density static RAMs are sensitive to radiation.
It involved designing a fault-tolerant controller and writing
a "fault-tolerant" software for the controller to perform the task.
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Software development
My favorites are assemblers for Intel 8080, 8048, 8051, Zilog Z80, and Motorola 68000 microprocessors.
My most favorite language is C and operating system UNIX with X-Windows/Motif environment.
In Science Systems, for real time applications we used
QNX system for IBM PC,
which is, in my opinion, one of the most finely written piece of software.
Telescope Control System
From summer 1995 till summer 1997 I worked on a telescope control system
for a 85-ton astronomical telescope with the 2-m (6.6ft) main mirror diameter.
The telescope is owned by the
Czech Academy of Sciences
and is located in Ondrejov, approximately 30km SW from Prague.
The dome of the telescope is in the picture on the right, which was taken
on December 15, 1997.
The project was prototype-like work, because the equipment is unique. For my
contribution to the project, please see my resume.
The control system runs on 3 IBM PC compatible computers under the
QNX real time operating system.
The user interface is written in X-Windows / Motif environment.
The system is being implemented on site now (February 1998).
More information about QNX
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QNX - manufacturer's home
page (in Canada)
Frequency synthesis
I have been interested in frequency synthesis for a long time. My interests include
phase locked loops (PLL) and direct digital synthesis.
Direct digital synthesis
To achieve very fine tuning steps with the least phase transient during switching,
the direct digital synthesis (DDS) method is the way to go. There are many DDS
chips available, sometimes called numerically controlled oscillators (NCO).
The DDS method uses a phase accumulator, driven by the specified frequency, which accumulates
the phase increments. The phase in incremented each driving frequency clock tick. The size of the
phase increment determines the actual output frequency. The binary width of the phase accumulator
(accumulator overflows) determines the minimum frequency, which is equal to the frequency
step, achievable by the DDS. The minimum frequency is defined by
and therefore the output frequency is
 ,
where F is a tuning number and n is the accumulator width in bits.
Clearly, the wider the accumulator is the finer frequency tuning step we can get. However, to convert
the phase to amplitude we ideally have to have a converted, which would take the n accumulated
phase bits as the input. Because look-up tables are mostly used for phase-to-sinusoid amplitude conversion,
with linearly increasing n the table size increases exponentially. Therefore, for all practical
purposes, the phase accumulator has to be truncated for the phase-to-sinusoid amplitude conversion and only
p most significant bits of the accumulator are used for the conversion. This causes spurious
spectral lines in the output spectrum. Another source of spurious lines is the D/A converter resolution
and physical characteristics.
DDS simulator
To simulate all of these features and also to simulate some dithering techniques for combating the spurious
signals caused by the phase accumulator truncation, I developed DDS simulator for MATLAB 5.
It uses the graphic user interface now available in MATLAB and the picture shows the DDS Simulator interface.
By clicking the picture or the DDS simulator link it is possible to download the simulator. There is also
more theory with more figures on that page.
- DDS simulator page - theory and files
in both UNIX tgzand DOS/Windows zip format.
There is also a list of the links to chips
and companies making DDS on chip, some of them even include phase/cos table
and a D/A converter on the chip.
Error correction coding
- 4i2i Communications - commercial error correction
software and hardware.
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A Library of Linear (and Nonlinear) Codes - maintained by N. J. A. Sloane.
- Neil J. A. Sloane - research
home page. Must see! There is much more than error correction codes, for example
on-line
encyclopedia of integer sequences, the catalogue of lattices, spherical codes,
Hadamard matrices, orthogonal arrays, etc.
- Turbo codes - page at
the University of Virginia.
- Turbo codes at Virginia Tech
- extensive information about turbo codes, incdluding very long list of turbo codes
references, turbo codes patents, links to other sites, commercial products, etc.
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Error Control Coding - programs in C and links. Page is in Japan.
Many programs for and Web pointers.
- Turbo codes at JPL
- Sergio Verdu
- home page at Princeton. There is a picture gallery with photographs
of many of the famous people in coding.
Mathematics
Some interesting mathematical links:
Digital signal processing
Links to industry general information
Typesetting, TeX, and LaTeX
TeX in general
- TUG - main page of TeX User Group.
- Directories - standart TeX directory structure.
- CTAN - WWW Interface to the Comprehensive
TeX Archive Network.
- TeX links - huge set of TeX (and LaTeX)
related links with pointers to different archives, commercial and free TeX
implementations and much much more.
LaTeX
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LaTeX Catalog Online - Complete CTAN Edition. Full listing of all entries in
the LaTeX Catalogue. The page contains pointers to different mirror all over
the world. Ultimate source of all LaTeX packages.
- (La)TeX Navigator -
aka A (La)TeX encyclopedia. In France, available in French, German, and English.
Nicely done with many links.
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CUED LaTeX guide - University of Cambridge LaTeX guide page.
- LaTeX help - on-line LaTeX help at
NASA server. Provides command descriptions and links to other help resources.
- CSLaTeX - Czech installation of LaTeX called based
on emTeX with special Czech fonts.
emTeX
My favourite installation of TeX for IBM PC computers is emTeX by Eberhard Mattes.
Typesetting
Links to sites related to typesetting and typography in general.
- Typebooks - site dedicated to
publications about typography with the comprehensive list of magazines
and books about typography.
- Glossary of printing terms
- Typozines -
list of links to the electronic magazines dealing with typography and graphic
design.
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