Transfer function

About: Transfer function is a research topic. Over the lifetime, 14362 publications have been published within this topic receiving 214983 citations. The topic is also known as: system function & network function.

Optimum estimation of time delay by a generalized correlator

Abstract: Optimum filters are designed to enhance the estimation of time delay between signals received at two spatially separate sensors. The resulting filters are placed in the predetection stage of a basic cross correlator. The transfer functions of the optimum filters are derived to operate according to two stated performance criteria. One selected criterion maximizes the expected peak at the time delay relative to the total background noise, and the other minimizes the difference between the incoming signal at the time delay and its estimated value. The flexibility and simplicity of the derivations lend themselves to the generalization of results and clarity of interpretation. The derived filters are contrasted with those found in the literature. One of the present filters is identical to that obtained by other authors when using the criterion of maximum likelihood. The reason for the difference between the present and maximum likelihood filters from the Eckart filter is pinpointed. Finally, the relationships among the various optimum and ad hoc filters are clarified.

Rapid identification of linear and nonlinear systems.

Abstract: Rapid parameter identification system for linear time-invariant plant with only input and output measurable

The geometric transfer function component for scintillation camera collimators with straight parallel holes.

Abstract: A theoretical approach has been developed that allows the geometric transfer function component for conventional scintillation camera collimators to be predicted in closed form. If transfer function analysis is to be useful in describing imaging system performance, the image of a point source must not depend on source position in a plane parallel to the detection plane. This shift invariance can be achieved by analysis of system response in terms of an effective point spread function, defined as the normalised image of a point source that would be obtained if the camera collimator were uniformly translated (but not rotated) during image formation. The geometric component of the corresponding effective transfer function is shown to be expressed simply by the absolute square of the two-dimensional Fourier transform of a collimator hole aperture, with the spatial frequency plane scaled by a factor which depends on collimator length, source-to-collimator distance, and collimator-to-detection plane distance. Closed form algebraic expressions of the geometric transfer function have been obtained for all four common hold shapes (circular, hexagonal, square and triangular). Monte Carlo simulations and experimental measurements have shown these theoretical expressions to be highly accurate.

Model matching by state feedback and dynamic compensation

Abstract: A new approach to the exact model matching problem is given based on an algorithm for characterizing the input-output structural properties of a linear system. In contrast to previous methods, the state feedback matching problem is solved without recourse to initial coordinate transformations. Moreover, the algorithm given here extends directly to the dynamic model matching problem and yields a set of necessary and sufficient conditions for one system to be transfer function equivalent via dynamic state feedback to a specified model system.

Analysis of charge-pump phase-locked loops

Abstract: In this paper, we present an exact analysis for third-order charge-pump phase-locked loops using state equations. Both the large-signal lock acquisition process and the small-signal linear tracking behavior are described using this analysis. The nonlinear state equations are linearized for the small-signal condition and the z-domain noise transfer functions are derived. A comparison to some of the existing analysis methods such as the impulse-invariant transformation and s-domain analysis is provided. The effect of the loop parameters and the reference frequency on the loop phase margin and stability is analyzed. The analysis is verified using behavioral simulations in MATLAB and SPECTRE.