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.

Plant rational transfer approximation from input-output data

Abstract: A rational transfer function model of the plant is generally desirable in feedback system design, when only plan input and output data are available over finite, sometimes incomplete, time intervals. This is especially so in a recent exact design technique for highly uncertain time-varying and non-linear plants. Here, the plants are replaced rigorously by an equivalent linear time-invariant plant set. Existing numerical techniques were found inadequate, especially in the high-frequency range, which is important in the design of feedback systems with large plant uncertainty. A technique was developed with excellent results, even for noisy data, unstable and non-minimum phase plants and severely truncated time intervals. The transfer function is calculated directly, without derivation of the input, output signal transforms. The operations involve repeated integrations of the data. Numerous examples are included.

Optimal choice of time-scaling factor for linear system approximations using Laguerre models

Abstract: Clowes (1965) illustrated how to select the optimal time-scaling factor for approximations of rational transfer functions using a series expansion of Laguerre functions. The present paper extends this result to approximations for general, L/sub 2/ stable, linear systems. As a direct application of this extended result, we are able to obtain approximations for irrational transfer functions which minimize the frequency domain error in the L/sub 2/ sense. Also, we give empirical solutions for the optimal time-scaling factor for approximations of first order plus delay systems which can then be applied to a larger class of overdamped systems. >

Classical sampling theorems in the context of multirate and polyphase digital filter bank structures

Abstract: The recovery of a signal from so-called generalized samples is a problem of designing appropriate linear filters called reconstruction (or synthesis) filters. This relationship is reviewed and explored. Novel theorems for the subsampling of sequences are derived by direct use of the digital-filter-bank framework. These results are related to the theory of perfect reconstruction in maximally decimated digital-filter-bank systems. One of the theorems pertains to the subsampling of a sequence and its first few differences and its subsequent stable reconstruction at finite cost with no error. The reconstruction filters turn out to be multiplierless and of the FIR (finite impulse response) type. These ideas are extended to the case of two-dimensional signals by use of a Kronecker formalism. The subsampling of bandlimited sequences is also considered. A sequence x(n) with a Fourier transform vanishes for mod omega mod >or=L pi /M, where L and M are integers with L >

Synthesis of Cross-Coupled Reduced-Order Dispersive Delay Structures (DDSs) With Arbitrary Group Delay and Controlled Magnitude

Abstract: For the first time, a systematic synthesis method for cross-coupled dispersive delay structures (DDSs) with controlled magnitude for analog signal processing applications is proposed. In this method, the transfer function is synthesized using a polynomial expansion approach, which allows to separately control the magnitude and group-delay response of the DDS. The synthesized transfer function also features a reduced order-namely, half-compared to that of previously reported synthesis techniques for linear-phase filters. Once it has been constructed, the transfer function is transferred into coupling matrices that can be implemented in arbitrary cross-coupled-resonator technologies. Several design examples are provided for different prescribed group-delay responses. An experimental waveguide prototype is demonstrated. The agreement between the measured and prescribed responses illustrates the proposed synthesis method.

Transfer functions for switched-capacitor and wave digital filters

Abstract: Closed-form expressions are presented for amplitude-oriented low-pass, high-pass, and bandpass sampled-data transfer functions suitable for realization as 1) switched-capacitor lossless discrete integrator (LDI) ladder filters, or 2) wave digital filters. Other types of realizations are also possible, such as those employing voltage inverter switches (VIS's), the recently introduced switched-capacitor "voltage wave" filters, and standard recursive digital realizations. The filters possess optimum equirippie (or maximally flat) passbands and monotonic stopbands with arbitrary selectivity. The low-pass and high-pass cases are derived from distributed passive prototype functions, but the more important bandpass functions are quite novel, appearing here for the first time.