The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Baruch Levush - One of the best experts on this subject based on the ideXlab platform.

  • Traveling-wave tube amplifier performance evaluation and design optimization for applications in digital communications with multilevel modulations
    IEEE Transactions on Microwave Theory and Techniques, 2003
    Co-Authors: Thomas M Antonsen, Bruce G. Danly, Baruch Levush
    Abstract:

    In this paper, we demonstrate the use of a Power Margin as a figure-of-merit for evaluating the performance and optimizing the design of traveling-wave tube amplifiers (TWTAs) used in digital communication applications with multilevel modulations. The Power Margin is a system-level measure that balances both device efficiency and nonlinear distortion and provides a more direct prediction of the system-level performance of Power amplifiers than device-level measures such as device efficiency or error-vector-magnitude. We calculate the Power Margin for M quadrature amplitude modulation for an existing TWTA to demonstrate the setting of an optimal amplifier operating drive level according to the criterion of the maximum Power Margin. The Power Margin can also be used to compare the performance of different traveling-wave tube (TWT) configurations. We compare the calculated Power-Margin performance for helix TWT circuits optimized with different optimization goal functions using the helix TWT design code CHRISTINE. The goal functions used in the optimization of the TWT circuits include AM/PM optimization, complex gain optimization, efficiency optimization, and a new digital goal function optimization. The digital goal function is shown to provide an enhanced Power Margin compared to the other three goal functions and demonstrates the potential of TWT device design optimization from a system perspective.

  • Traveling-wave tube amplifier performance evaluation and design optimization for applications in multi-level digital communications
    2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278), 1
    Co-Authors: J.x. Qiu, Bruce G. Danly, Thomas M Antonsen, David K. Abe, Baruch Levush
    Abstract:

    In this paper, we use Power Margin as a figure of merit for evaluating the performance of TWT amplifiers used in multi-level digital communications applications. Power Margin is better at predicting the system level performance of TWT amplifiers than device-level measures like EVM. We compare the calculated Power Margin performances for helix TWT circuits optimized with different optimization goal functions in CHRISTINE. A digital goal function that provides enhanced Power Margin is constructed to demonstrate the approach of TWT circuit design optimization from a system perspective.

Ian Dobson - One of the best experts on this subject based on the ideXlab platform.

  • Computation of closest bifurcations in Power systems
    IEEE Transactions on Power Systems, 1994
    Co-Authors: Fernando L. Alvarado, Ian Dobson
    Abstract:

    Voltage collapse and blackout can occur in an electric Power system when load Powers vary so that the system loses stability in a saddle node bifurcation. This paper computes load Powers at which bifurcation occurs and which are locally closest to given operating load Powers. The distance in load Power parameter space to this locally closest bifurcation is an index of voltage collapse and a minimum load Power Margin. The computations are illustrated for several Power systems. Monte-Carlo optimization techniques are applied to obtain multiple minimum load Power Margins. The use of load Power Margin sensitivities to select system controls is discussed. >

  • new methods for computing a closest saddle node bifurcation and worst case load Power Margin for voltage collapse
    IEEE Transactions on Power Systems, 1993
    Co-Authors: Ian Dobson, L Lu
    Abstract:

    Voltage collapse and blackout can occur in an electric Power system when load Powers vary so that the system loses stability in a saddle node bifurcation. The authors propose new iterative and direct methods to compute load Powers at which bifurcation occurs and which are locally closest to the current operating load Powers. The distance in load Power parameter space to this locally closest bifurcation is an index of voltage collapse. The pattern of load Power increase need not be predicted; instead the index is a worst case load Power Margin. The computations are illustrated in the six-dimensional load Power parameter space of a five bus Power system. The normal vector and curvature of a hypersurface of critical load Powers at which bifurcation occurs are also computed. The sensitivity of the index to parameters and controls is easily obtained from the normal vector. >

  • computing an optimum direction in control space to avoid stable node bifurcation and voltage collapse in electric Power systems
    IEEE Transactions on Automatic Control, 1992
    Co-Authors: Ian Dobson, L Lu
    Abstract:

    Given a load Power forecast, the sensitivity with respect to controls of a load Power Margin measuring proximity to voltage collapse is computed. The computation is simple enough to contribute to the practical planning and control of a Power system to avoid voltage collapse blackouts. The computation applies to avoiding saddle node bifurcation instability of a general dynamical system. >

  • voltage collapse precipitated by the immediate change in stability when generator reactive Power limits are encountered
    IEEE Transactions on Circuits and Systems I-regular Papers, 1992
    Co-Authors: Ian Dobson
    Abstract:

    When a generator of a heavily loaded electric Power system reaches a reactive Power limit, the system can become immediately unstable and a dynamic voltage collapse leading to blackout may follow. The statics and dynamics of this mechanism for voltage collapse are studied by example and by the generic theory of saddle node and transcritical bifurcations. It is shown that load Power Margin calculations can be misleading if the immediate instability phenomenon is neglected. >

Thomas M Antonsen - One of the best experts on this subject based on the ideXlab platform.

  • Traveling-wave tube amplifier performance evaluation and design optimization for applications in digital communications with multilevel modulations
    IEEE Transactions on Microwave Theory and Techniques, 2003
    Co-Authors: Thomas M Antonsen, Bruce G. Danly, Baruch Levush
    Abstract:

    In this paper, we demonstrate the use of a Power Margin as a figure-of-merit for evaluating the performance and optimizing the design of traveling-wave tube amplifiers (TWTAs) used in digital communication applications with multilevel modulations. The Power Margin is a system-level measure that balances both device efficiency and nonlinear distortion and provides a more direct prediction of the system-level performance of Power amplifiers than device-level measures such as device efficiency or error-vector-magnitude. We calculate the Power Margin for M quadrature amplitude modulation for an existing TWTA to demonstrate the setting of an optimal amplifier operating drive level according to the criterion of the maximum Power Margin. The Power Margin can also be used to compare the performance of different traveling-wave tube (TWT) configurations. We compare the calculated Power-Margin performance for helix TWT circuits optimized with different optimization goal functions using the helix TWT design code CHRISTINE. The goal functions used in the optimization of the TWT circuits include AM/PM optimization, complex gain optimization, efficiency optimization, and a new digital goal function optimization. The digital goal function is shown to provide an enhanced Power Margin compared to the other three goal functions and demonstrates the potential of TWT device design optimization from a system perspective.

  • Traveling-wave tube amplifier performance evaluation and design optimization for applications in multi-level digital communications
    2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278), 1
    Co-Authors: J.x. Qiu, Bruce G. Danly, Thomas M Antonsen, David K. Abe, Baruch Levush
    Abstract:

    In this paper, we use Power Margin as a figure of merit for evaluating the performance of TWT amplifiers used in multi-level digital communications applications. Power Margin is better at predicting the system level performance of TWT amplifiers than device-level measures like EVM. We compare the calculated Power Margin performances for helix TWT circuits optimized with different optimization goal functions in CHRISTINE. A digital goal function that provides enhanced Power Margin is constructed to demonstrate the approach of TWT circuit design optimization from a system perspective.

Bruce G. Danly - One of the best experts on this subject based on the ideXlab platform.

  • Traveling-wave tube amplifier performance evaluation and design optimization for applications in digital communications with multilevel modulations
    IEEE Transactions on Microwave Theory and Techniques, 2003
    Co-Authors: Thomas M Antonsen, Bruce G. Danly, Baruch Levush
    Abstract:

    In this paper, we demonstrate the use of a Power Margin as a figure-of-merit for evaluating the performance and optimizing the design of traveling-wave tube amplifiers (TWTAs) used in digital communication applications with multilevel modulations. The Power Margin is a system-level measure that balances both device efficiency and nonlinear distortion and provides a more direct prediction of the system-level performance of Power amplifiers than device-level measures such as device efficiency or error-vector-magnitude. We calculate the Power Margin for M quadrature amplitude modulation for an existing TWTA to demonstrate the setting of an optimal amplifier operating drive level according to the criterion of the maximum Power Margin. The Power Margin can also be used to compare the performance of different traveling-wave tube (TWT) configurations. We compare the calculated Power-Margin performance for helix TWT circuits optimized with different optimization goal functions using the helix TWT design code CHRISTINE. The goal functions used in the optimization of the TWT circuits include AM/PM optimization, complex gain optimization, efficiency optimization, and a new digital goal function optimization. The digital goal function is shown to provide an enhanced Power Margin compared to the other three goal functions and demonstrates the potential of TWT device design optimization from a system perspective.

  • Traveling-wave tube amplifier performance evaluation and design optimization for applications in multi-level digital communications
    2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278), 1
    Co-Authors: J.x. Qiu, Bruce G. Danly, Thomas M Antonsen, David K. Abe, Baruch Levush
    Abstract:

    In this paper, we use Power Margin as a figure of merit for evaluating the performance of TWT amplifiers used in multi-level digital communications applications. Power Margin is better at predicting the system level performance of TWT amplifiers than device-level measures like EVM. We compare the calculated Power Margin performances for helix TWT circuits optimized with different optimization goal functions in CHRISTINE. A digital goal function that provides enhanced Power Margin is constructed to demonstrate the approach of TWT circuit design optimization from a system perspective.

L Lu - One of the best experts on this subject based on the ideXlab platform.

  • new methods for computing a closest saddle node bifurcation and worst case load Power Margin for voltage collapse
    IEEE Transactions on Power Systems, 1993
    Co-Authors: Ian Dobson, L Lu
    Abstract:

    Voltage collapse and blackout can occur in an electric Power system when load Powers vary so that the system loses stability in a saddle node bifurcation. The authors propose new iterative and direct methods to compute load Powers at which bifurcation occurs and which are locally closest to the current operating load Powers. The distance in load Power parameter space to this locally closest bifurcation is an index of voltage collapse. The pattern of load Power increase need not be predicted; instead the index is a worst case load Power Margin. The computations are illustrated in the six-dimensional load Power parameter space of a five bus Power system. The normal vector and curvature of a hypersurface of critical load Powers at which bifurcation occurs are also computed. The sensitivity of the index to parameters and controls is easily obtained from the normal vector. >

  • computing an optimum direction in control space to avoid stable node bifurcation and voltage collapse in electric Power systems
    IEEE Transactions on Automatic Control, 1992
    Co-Authors: Ian Dobson, L Lu
    Abstract:

    Given a load Power forecast, the sensitivity with respect to controls of a load Power Margin measuring proximity to voltage collapse is computed. The computation is simple enough to contribute to the practical planning and control of a Power system to avoid voltage collapse blackouts. The computation applies to avoiding saddle node bifurcation instability of a general dynamical system. >