The design and implementation of modula for the Burroughs B1700 computer

This thesis describes the design and implementation of a Modula compiler for the Burroughs 81700 computer, suitable for implementing an alternative operating system to that supplied by the manufacturer. Modula is a modern, high - level multiprogramm1ng language designed for real-time applications. The 81700 is a dynamically microprogrammable computer , with an unusual architecture. The i mplementation of Modula on the 81700 provides an opportunity to investigate some of the ramifications of the machine's architecture. The 81700 computer is first described, followed by a discussion of the Modula dialect implemented. The v irtual Modula machine, implement ed in microcode, is presented next. Features and structure of the Modula compiler and the 81700 microprograms are discussed, and the thesis concludes with some general remarks. Several appendices are included

A Novel Three-Point Modulation Technique for Fractional-N Frequency Synthesizer Applications

This paper presents a novel three-point modulation technique for fractional-N frequency synthesizer applications. Convention modulated fractional-N frequency synthesizers suffer from quantization noise, which degrades not only the phase noise performance but also the modulation quality. To solve this problem, this work proposes a three-point modulation technique, which not only cancels the quantization noise, but also markedly boosts the channel switching speed. Measurements reveal that the implemented 2.4 GHz fractional-N frequency synthesizer using three-point modulation can achieve a 2.5 Mbps GFSK data rate with an FSK error rate of only 1.4 %. The phase noise is approximately -98 dBc/Hz at a frequency offset of 100 kHz. The channel switching time is only 1.1 μs with a frequency step of 80 MHz. Comparing with conventional two-point modulation, the proposed three-point modulation greatly improves the FSK error rate, phase noise and channel switching time by about 10 %, 30 dB and 126 μs, respectively

A Language-Independent Garbage Collector Toolkit

We describe a memory management toolkit for language implementors. It offers efficient and flexible generation scavenging garbage collection. In addition to providing a core of languageindependent algorithms and data structures, the toolkit includes auxiliary components that ease implementation of garbage collection for programming languages. We have detailed designs for Smalltalk and Modula-3 and are confident the toolkit can be used with a wide variety of languages. The toolkit approach is itself novel, and our design includes a number of additional innovations in flexibility, efficiency, accuracy, and cooperation between the compiler and the collector

Expression and Composition of Design Patterns with AspectJ

National audienceDesign patterns are well-known couples of problems-solutions for software engineer- ing. By nature, they often lack support from languages and this further complicates the study of their composition in the code. Aspect-oriented languages provide new mechanisms for modula- rization, which can help to improve design patterns implementation. (Hannemann et al., 2002) is the first extensive study of patterns aspectization with AspectJ. We notice some AspectJ idioms are needed in order to implement object relationships. We give a more reusable VISITOR pat- tern. We highlight a reusable composition of COMPOSITE and VISITOR patterns and expressive interactions of the OBSERVER pattern with a tree structure. We thus show that modularization by aspects helps composition of design patterns

Hybrid M-FSK/DQPSK Modulations for CubeSat Picosatellites

Conventional CubeSat radio systems typically use one of several basic modulations, such as AFSK, GMSK, BPSK, QPSK and OOK or switch between them on demand if possible. These modulations represent a bal¬anced trade-off between good energy efficiency of high order M-FSK modulation and good spectral efficiency of high order M-QAM modulation. Utilization of modulations with the best energy efficiency is not possible due to strict limits on occupied frequency bandwidth. In this paper the proposed group of hybrid modulations and proposed hybrid modulator and demodulator are presented. Novel solution offer interesting possibilities of increasing spectral efficiency as well as energy efficiency of basic M-FSK modulation by embedding DQPSK symbols between two M-FSK symbols. Such group of hybrid modulations offers suitable properties for picosatellite, e.g. simple realization onboard the picosatellite, better energy and spectral efficiency, low PAPR, wide range of adaptation by changing the order of M-FSK, suitable for easy non-coherent demodulation, good immunity to Doppler effect with DM-FSK coding

Fast Recompilation of Object Oriented Modules

Once a program file is modified, the recompilation time should be minimized, without sacrificing execution speed or high level object oriented features. The recompilation time is often a problem for the large graphical interactive distributed applications tackled by modern OO languages. A compilation server and fast code generator were developed and integrated with the SRC Modula-3 compiler and Linux ELF dynamic linker. The resulting compilation and recompilation speedups are impressive. The impact of different language features, processor speed, and application size are discussed