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Newsletters - MATLAB Digest
Past Issues
March 1998
Volume 6, number 1
The MATLAB® Digest is The MathWorks electronic news bulletin for MathWorks Account members. You can expect to receive it at the end of each quarter. The MATLAB Digest can be sent directly to you. To subscribe, become a member.
Technical Examples & Tips
"Electrohydraulic Servo Control" by Stan
Quinn
This article, entitled "Electrohydraulic Servo Control",
introduces an example in which Simulink® and Stateflow™ are
used to create a simulation model for a hydraulic servomechanism. The
hydraulic servo is controlled by a pulse-width modulated (PWM) solenoid.
This mechanism could be used as a system in an industrial or manufacturing
setting or as a subsystem controlling the position of a valve in an
aerospace or automotive application. The magnetic, hydraulic, and mechanical
components and the control law are represented in Simulink while the
electronic circuit that interfaces the PWM waveform to the solenoid
is best modeled in Stateflow.
The article explains the principles of the physical situation, and
presents the equations that represent the system. It shows how to proceed
from the physical equations to the Simulink block diagram. Once the
Simulink model has been completed, we run the simulation, analyze the
results, and draw conclusions from the study. 
read
more
UINT8 Data Type for Image Processing
In the Image Processing Toolbox version 2.0 a new data type, uint8,
was introduced to help minimize the amount of memory necessary for
the storage of image data files. The data in the uint8 arrays is
stored as 8-bit unsigned integers and therefore requires one-eighth
as much memory as a double array.
MATLAB provides limited support for operations on uint8 arrays. IMREAD reads images into MATLAB as uint8 arrays, and the IMAGE and IMAGESC functions can display uint8 images.
User Contributed M-Files
Isosurface package for MATLAB version 5.0 Created by Lennart
Bengtsson 11/3/97
The M-files and MEX-files in this tar file provide isosurface support
in MATLAB. An isosurface is the 3-D analogue of a 2-D contour line
and is defined by the solution of the equation f(x,y,z) = constant.
Isosurfaces are very useful for visualizing 3-D data.
Kepler Problem for Orbit Intersection Created by Russ
Sexton 12/29/97
This is a solution for the Kepler problem for orbit insertion. Given
a burn out velocity and a flight path angle, the apogee of the orbit
and the circular orbit that can be achieved with one burn at apogee
will be calculated. The delta-velocity for circularization is also
plotted. Several other planets besides Earth are included and you can
simply adjust the initial parameters to perform orbital analysis of
several planets in our home solar system. View this
M-file.
Viewing and Printing Sound Spectrograms Created by Dave
Mellinger 9/3/97
Osprey, version 1.3.1, is a program for viewing and printing spectrograms
of sound files. It allows you to change various parameters that affect
the computation and display of spectrograms, including the time/bandwidth
tradeoff, the window type, and display brightness. It computes and
caches spectrogram values on demand, minimizing computation time. It
also allows manual logging of information about the sound (time, frequency,
energy, etc.) for use in acoustic analysis.
The user-contributed archive is a service to the MATLAB community -- a place where MATLAB users can communicate ideas to one another. It is not a depository of MathWorks approved software; no warranties, expressed or implied, are made by The MathWorks that the M/MEX files contained in the archive are error free. Use of these programs is at the user's own risk and The MathWorks disclaims all liability for injury or damage that may result from their use.
Visit the User Community for more user contributed M-Files and for submission instructions.
Product Releases
Release 10 is now shipping. Some highlights include:
The MATLAB 5 compatible Compiler extends MATLAB by providing automatic C and C++ code generation of M-file programs directly from MATLAB. The MATLAB C and C++ Math Libraries make the core mathematical capabilities of MATLAB available outside the MATLAB environment.
Power System Blockset 1.0: The new Power System Blockset for MATLAB 5.2 and Simulink 2.2 allows you to model and simulate the generation, transmission, and consumption of electrical power within Simulink.
Control System Toolbox 4.1: New features are included to support an interactive environment for classical and modern control system design, analysis, and modeling. Features include the LTI Viewer (analysis tool) now accessible from Simulink and the Root Locus Design graphical user interface.
DSP Blockset 2.2: New features include filter realization wizard for constructing filters with different architectures, frame-based processing, and new blocks for variable delays, discrete cosine transform and spectral estimation.
Neural Network Toolbox 3.0: Recent enhancements include modular network representation, new network types and training algorithms, pre- and post-processing functions, and enhanced Simulink support.
Signal Processing Toolbox 4.1: Recent additions include enhancements to filter designer, additional spectral analysis methods, new algorithm features including additional filter design methods and multirate filter bank implementation.
Visit the MathWorks Products page for current information on all products.
MATLAB Based Books: New Titles
"DSP First: A Multimedia Approach" is a hands-on multimedia package for learning about DSP applications, multimedia signals, and MATLAB.
"Mastering MATLAB 5: A Comprehensive Tutorial and Reference" provides a 'learn while doing' approach covering all aspects of MATLAB 5.
"Mastering SIMULINK 2", both a tutorial and a reference, covers all of the important capabilities of Simulink 2, including subsystems, masking, callbacks, and S-Functions.
"Modern Control Systems, 8e" presents a control engineering methodology that stresses physical system modeling and practical control system designs.
The MathWorks supports authors of books that incorporate MATLAB, Simulink, toolboxes, or blocksets in the text. For a complete list of books or more information about this program visit MATLAB Based Books.
You can access our Technical Support solutions database 24 hours a day for the fastest answers to your technical problems.
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