Topic
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.
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01 Jan 2004
TL;DR: Preface.
Abstract: Preface. Measurement systems. Instrumentation systems elements. Instrumentation case studies. Control Systems. Process controllers. Correction elements. PLC systems. Systems. Transfer function. Systems response. Frequency response. Nyquist diagrams. Controllers. Appendices: Errors. Differential equations. Laplace transform. Answers. Index.
48 citations
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TL;DR: The theoretical principle underlying this compressive technique is presented, defining the key parameters affecting the information retrieval from a measured frequency signal and the prior characterization of the compressive device's transfer functions.
Abstract: This paper presents a compressive technique that simplifies the architecture of multiple-input multiple-output (MIMO) radar imaging systems. By means of a passive device connected to an MIMO array of antennae, a novel approach is introduced to extract the interaction between antennae from a compressed signal measured between two ports. This technique relies on a multiplexing principle that exploits the frequency diversity and it is thus particularly suitable for ultrawideband imaging systems. This paper presents the theoretical principle underlying this compressive technique, defining the key parameters affecting the information retrieval from a measured frequency signal and the prior characterization of the compressive device’s transfer functions. Simulations are performed to demonstrate the potential of the technique for MIMO ultrawideband imaging systems and its compatibility with fast range migration algorithms based on fast Fourier transforms. Finally, an experimental validation is performed with a two-dimensional radiating aperture connected to a compressive device, allowing for the three-dimensional near-field imaging of different targets.
48 citations
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TL;DR: An error bound for transfer function order reduction is derived, when frequency weighted balanced truncation is the order reduction method and the bound is valid for both one-sided and two-sided weighted balancing approximations with stable weights.
48 citations
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24 May 1982
TL;DR: In this article, a process control apparatus is provided which has a PID controller to which is supplied a sampled signal of a control deviation signal of process value signal and a reference signal and which generates a PID control signal according to sampled-value PID control constants.
Abstract: A process control apparatus is provided which has a PID controller to which is supplied a sampled signal of a control deviation signal of a process value signal and a reference signal and which generates a PID control signal according to sampled-value PID control constants. A non-linear controller is connected in parallel with the PID controller. A sum signal of the output signals from the PID controller and the non-linear controller is supplied to a process through a holding circuit. The process control apparatus further includes a circuit for identifying the dynamic characteristic of the process according to the sum signal and the sampled signal of the process value, and a circuit for calculating a transfer function of the process in the Laplace operator domain and for determining the sampled-value PID constants of the PID controller according to the dynamic characteristic.
48 citations
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TL;DR: An efficient raw signal generation method based on equivalent scatterer and subaperture processing for the one-stationary bistatic synthetic aperture radar (SAR) that considers the moving platform's motion error to generate the precise raw signal for real SAR systems.
Abstract: This paper presents an efficient raw signal generation method based on equivalent scatterer and subaperture processing for the one-stationary bistatic synthetic aperture radar (SAR). It considers the moving platform's motion error to generate the precise raw signal for real SAR systems. First, the imaging geometry in elliptical polar coordinates is built, and then, the scene is divided into several equidistant elliptical rings. Based on the equivalent scatterer model, the approximate SAR system transfer function is derived; thus, each pulse's raw signal is calculated by the convolution of the transmitted signal and transfer function, via the fast Fourier transform (FFT). To further improve the simulation speed, the subaperture and subscene processing is used. The transfer function for the same subaperture's pluses is calculated simultaneously by the weighted sum of all subscenes' equivalent scattering coefficient in the same equidistant elliptical ring, which is performed by the nonuniform FFT (NUFFT). This method only involves the FFT, NUFFT, and complex multiplication, which means the easier operation and higher efficiency. The implementation, limitation, and evaluation of the proposed method are discussed. Simulation results are given to prove the correctness and validity of the proposed method.
48 citations