Showing papers on "Performance prediction published in 1977"
TL;DR: An analysis of an asynchronous phase-coded spread-spectrum multiple-access communication system reveals which code parameters have the greatest impact on communication performance and provides analytical tools for use in preliminary system design.
Abstract: An analysis of an asynchronous phase-coded spread-spectrum multiple-access communication system is presented. The results of this analysis reveal which code parameters have the greatest impact on communication performance and provide analytical tools for use in preliminary system design. Emphasis is placed on average performance rather than worst-case performance and on code parameters which can be computed easily.
1,723 citations
01 Oct 1977
TL;DR: A rating hypothesis is introduced which relates the numerical pilot opinion rating assigned to a particular vehicle andtask to the numerical value of the index of performance resulting from an optimal pilot modeling procedure as applied to that vehicle and task.
Abstract: A brief review of some of the more pertinent applications of analytical pilot models to the prediction of aircraft handling qualities is undertaken. The relative ease with which multiloop piloting tasks can be modeled via the optimal control formulation makes the use of optimal pilot models particularly attractive for handling qualities research. To this end, a rating hypothesis is introduced which relates the numerical pilot opinion rating assigned to a particular vehicle and task to the numerical value of the index of performance resulting from an optimal pilot modeling procedure as applied to that vehicle and task. This hypothesis is tested using data from piloted simulations and is shown to be reasonable. An example concerning a helicopter landing approach is introduced to outline the predictive capability of the rating hypothesis in multiaxis piloting tasks.
70 citations
TL;DR: In this paper, the authors have shed further light on the operating characteristics and limitations of IMPATT diodes, particularly those with Read or modified Read structures, by developing efficient and economical computer programs which incorporate all of the important material parameters and doping profiles in an exact manner.
Abstract: The purpose of this paper is to shed further light on the operating characteristics and limitations of IMPATT diodes, particularly those with Read or modified Read structures. This has been achieved by developing efficient and economical computer Programs which incorporate all of the important material parameters and doping profiles in an exact manner. These computer programs are then employed to study the properties of high-efficiency Si and GaAs structures. Some very interesting properties of these devices and the effects of material parameters and doping profiles on their performance are presented and discussed. This leads to a better understanding of these devices and their limitations. Preliminary calculations have also been carried out on an InP IMPATT diode and the results are presented.
41 citations
36 citations
14 Jun 1977
TL;DR: A linear continuous low frequency small signal model, valid for all types of converters (boost,buck, buck boost), both in heavy and light modes, is presented and a computer program, using state analysis, has been developed allowing the automatic performance analysis of complete controlled converters.
Abstract: A linear continuous low frequency small signal model, valid for all types of converters (boost,buck, buck boost), both in heavy and light modes, is presented in this paper. Its interesting characteristics are that it is valid for free running as well as for fixed frequency converters and that it allows easily to take into account both input and output filters. Thanks to its modularity and its simple general form, it gives a strong insight into the influence of various parameters. (such as input filters) on performance dynamics and into the design of efficient control loops. Finally, a computer program, using state analysis, has been developed allowing the automatic performance analysis of complete controlled converters.
19 citations
TL;DR: A flexible accurate large-signal computer program has been developed for the design of coupled-cavity traveling wave tubes and good agreement was obtained between the predictions of the program and the measured performance of the flight tube.
Abstract: A flexible accurate large-signal computer program has been developed for the design of coupled-cavity traveling wave tubes. The program is written for a TSS-360 time sharing system. The beam is described by a disk model and the slow wave structure by a sequence of cavities or cells. The computational approach is arranged so that each cavity may have different geometrical or electrical parameters than its neighbors. This allows the program user to simulate a tube of almost arbitrary complexity. Input and output couplers, severs, complicated velocity tapers, and other features peculiar to one or a few cavities may be modeled by a correct choice of input data. The beam-wave interaction is handled by a new approach in which the RF fields are expanded in solutions to the TM wave equation retaining all significant space harmonics. The program was used to perform a design study of the TWT developed for the CTS satellite. Good agreement was obtained between the predictions of the program and the measured performance of the flight tube. The internal check on power balance was satisfied within ±0.2 percent of input beam power.
17 citations
TL;DR: A simplified technique to predict yearly system performance was developed, based on a computation of the system performance for a single “average” day of each month, modifying this result with a correction factor, and summing the results over each month of the heating season.
13 citations
01 Feb 1977
TL;DR: The turbine developed design specific work output at design speed at a total pressure ratio of 6.745 with a corresponding efficiency of 0.855 as mentioned in this paper, which was 3.1 points lower than the estimated efficiency quoted by the contractor in the design report and 0.7 of a point lower than that determined by a reference prediction method.
Abstract: The turbine developed design specific work output at design speed at a total pressure ratio of 6.745 with a corresponding efficiency of 0.855. The efficiency (0.855)was 3.1 points lower than the estimated efficiency quoted by the contractor in the design report and 0.7 of a point lower than that determined by a reference prediction method. The performance of the turbine, which was a forced vortex design, agreed with the performance determined by the prediction method to about the same extent as did the performance of three reference high stage loading factor turbines, which were free vortex designs.
7 citations
TL;DR: Those factors which influence the design of highspeed optical preamplifiers are described, and the exchange between bandwidth and noise in a shunt-feedback first stage is examined.
Abstract: We describe those factors which influence the design of highspeed optical preamplifiers, and examine the exchange between bandwidth and noise in a shunt-feedback first stage. For a given preamplifier bandwidth, it is shown that an operating point exists which minimises the amplifier noise level.
TL;DR: In this article, a gallium arsenide diode structure is simulated using a particle-mesh computer model, which incorporates two dimensions in configuration space, and three dimensions in k-space, with a full description of the material scattering cross-section, which is implemented using Monte-Carlo techniques.
Abstract: A gallium arsenide diode structure is simulated using a particle-mesh computer model. The model incorporates two dimensions in configuration space, and three dimensions in k-space, with a full description of the material scattering cross-section, which is implemented using Monte-Carlo techniques. Detailed information about electric field and valley population profiles is presented for both dipole domain, and l.s.a. modes of operation. Comparison is made with the widely differing previous theoretical results.
01 May 1977
TL;DR: In this paper, the design emphasis is to start with the simplest system configuration that experience indicates would be practical, and a digital computer program is used to select that set of parameter values which minimizes the performance index.
Abstract: Parameter optimization techniques for the design of linear automatic control systems that are applicable to both continuous and digital systems are described. The model performance index is used as the optimization criterion because of the physical insight that can be attached to it. The design emphasis is to start with the simplest system configuration that experience indicates would be practical. Design parameters are specified, and a digital computer program is used to select that set of parameter values which minimizes the performance index. The resulting design is examined, and complexity, through the use of more complex information processing or more feedback paths, is added only if performance fails to meet operational specifications. System performance specifications are assumed to be such that the desired step function time response of the system can be inferred.
01 Aug 1977
01 Jan 1977
TL;DR: In this paper, a flexible accurate large-signal computer program for the design of coupled-cavity traveling wave tubes was developed for a TSS-360 time sharing system.
Abstract: A flexible accurate large-signal computer program has been developed for the design of coupled-cavity traveling wave tubes. The program is written for a TSS-360 time sharing system. The beam is described by a disk model and the slow wave structure by a sequence of cavities or cells. The computational approach is arranged so that each cavity may have different geometrical or electrical parameters than its neighbors. This allows the program user to simulate a tube of almost arbitrary complexity. Input and output couplers, severs, complicated velocity tapers, and other features peculiar to one or a few cavities may be modeled by a correct choice of input data. The beam-wave interaction is handled by a new approach in which the RF fields are expanded in solutions to the TM wave equation retaining all significant space harmonics. The program was used to perform a design study of the TWT developed for the CTS satellite. Good agreement was obtained between the predictions of the program and the measured performance of the flight tube. The internal check on power balance was satisfied within ±0.2 percent of input beam power.
01 Jan 1977
01 Jul 1977
TL;DR: Techniques developed to estimate power gain, delay, signal-to-noise ratio, and mean square error in digital computer simulations of lowpass and bandpass systems show to be accurate and quite versatile in evaluating the performance of many systems through digital computer simulation.
Abstract: Techniques are developed to estimate power gain, delay, signal-to-noise ratio, and mean square error in digital computer simulations of lowpass and bandpass systems The techniques are applied to analog and digital communications The signal-to-noise ratio estimates are shown to be maximum likelihood estimates in additive white Gaussian noise The methods are seen to be especially useful for digital communication systems where the mapping from the signal-to-noise ratio to the error probability can be obtained Simulation results show the techniques developed to be accurate and quite versatile in evaluating the performance of many systems through digital computer simulation
01 Jan 1977
01 Jan 1977
Proceedings Article•
01 Jan 1977
01 Jan 1977
TL;DR: An analytical method is developed for determining the basic RF link parameters that are required in a satellite system design and can be used to rapidly assess tradeoffs in various system elements.
Abstract: An analytical method is developed for determining the basic RF link parameters that are required in a satellite system design. Certain simplifying assumptions are required and specific system elements are selected. Two different design criteria are considered; optimizing the per-beam signal energy to noise spectral density ratio (Eb/N0), and minimizing the per-user costs. These two criteria are complements of each other subject to coverage and performance constraints. The model can be used to rapidly assess tradeoffs in various system elements. A specific example of a domestic satellite system is considered. The economic analyses are also considered and the economy of scale effect is demonstrated for the design example and considered.
01 May 1977