Jvm 規范說明。The Java Virtual Machine was designed to support the Java programming language. Some concepts and vocabulary from the Java language are thus necessary to understand the virtual machine. This chapter gives enough of an overview of Java to support the discussion of the Java Virtual Machine to follow. Its material has been condensed from The Java Language Specification, by James Gosling, Bill Joy, and Guy Steele. For a complete discussion of the Java language, or for details and examples of the material in this chapter, refer to that book. Readers familiar with that book may wish to skip this chapter. Readers familiar with Java, but not with The Java Language Specification, should at least skim this chapter for the terminology it introduces.
I often need a simple function generator. Just to generate a certain frequency. After all the years I ve worked with electronics, I still haven t got me one. Even though I need it now and then, I just couldn t seem to justify the cost of one.
So, standard solution - build one yourself.
I designed a simple sinewave generator based on a Analog Devices AD9832 chip. It will generate a sinewave from 0.005 to 12 MHz in 0.005 Hz steps.
That s pretty good, and definitely good enough for me ! But while waiting for the AD9832 chip to arrive, I came up with a very simple version of the DDS synth, using just the 2313 and a resistor network.
Linux was first released into an unsuspecting world in the summer of 1991. Initially
the spare-time hobby of a Finnish computer scientist by the name of Linus Torvalds,
Linux was at first accessible only in software source code form to those with enough
expertise to build and install it. Early enthusiasts (most also developers themselves by
necessity) exploited the growth of the Internet in the early 1990s as a means to build
online communities and drive development forward. These communities helped to
build the first Linux software distributions, containing all the software components
needed to install and use a Linux system without requiring users to be technical experts.
Reads/writes text as a character stream, buffering characters so as to provide for the efficient reading/writing of characters, arrays, and lines.
The buffer size may be specified, or the default size may be used. The default is large enough for most purposes.
In general, each read request made of a Reader causes a corresponding read request to be made of the underlying character or byte stream. It is therefore advisable to wrap a BufferedReader around any Reader whose read() operations may be costly, such as FileReaders and InputStreamReaders.
MCPU is a minimal cpu aimed to fit into a 32 Macrocell CPLD - one of the smallest available programmable logic devices. While this CPU is not powerful enough for real world applications it has proven itself as a valuable educational tool. The source code is just a single page and easily understood. Both VHDL and Verilog versions are supplied. The package comes with assembler, emulator and extensive documentation.
pHash is an implementation of various perceptual hashing algorithms. A perceptual hash is a fingerprint of an audio, video, or image file that is mathematically based on the audio or visual content contained within. Unlike cryptographic hash functions that rely on the avalanche effect of small changes in input leading to drastic changes in the output, perceptual hashes are "close" to one another if the inputs are visually or auditorily similar. As a result, perceptual hashes must also be robust enough to take into account transformations that could have been performed on the input.
This article covers many of the fundamentals of analog video. Video is defined for our purposes here as "moving
pictures." Still imaging, like what is found in digital still cameras or scanners, is not covered. The requirements
for still imaging do have a lot in common with those for video, but the differences are significant enough to be
dealt with as a separate discipline.
the book provides many solved examples that illustrate the principles involved,
and includes, in addition, two chapters that deal exclusively with applications of
unconstrained and constrained optimization methods to problems in the areas of
pattern recognition, control systems, robotics, communication systems, and the
design of digital filters. For each application, enough background information
is provided to promote the understanding of the optimization algorithms used
to obtain the desired solutions.
High volume USB 2.0 devices will be designed using ASIC technology with embedded USB 2.0 support.
For full-speed USB devices the operating frequency was low enough to allow data recovery to be handled
in a vendors VHDL code, with the ASIC vendor providing only a simple level translator to meet the USB
signaling requirements. Today s gate arrays operate comfortably between 30 and 60 MHz. With USB 2.0
signaling running at hundreds of MHz, the existing design methodology must change.
High volume USB 2.0 devices will be designed using ASIC technology with embedded USB 2.0 support.
For full-speed USB devices the operating frequency was low enough to allow data recovery to be handled
in a vendors VHDL code, with the ASIC vendor providing only a simple level translator to meet the USB
signaling requirements. Today s gate arrays operate comfortably between 30 and 60 MHz. With USB 2.0
signaling running at hundreds of MHz, the existing design methodology must change.
