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.

Analytical fractional PID controller design based on Bode's ideal transfer function plus time delay.

Abstract: In this paper, a fractional order PID controller cascaded with a fractional filter is proposed for higher order processes. In this analytical design methodology, one or two reduced fractional orders plus time delay models are used to represent higher order system transfer functions. The controller parameters are determined so as to meet certain frequency domain specifications. A unity feedback reference model is employed where Bode's ideal loop transfer function plus time delay of the fractional order model is placed in the forward path. The addition of this time delay provides the exact determination of frequency domain specifications if the system either intrinsically owns a time delay or a time delay is injected by its reduced order model. The proposed methodology is compared with two other related methodologies and it has been observed that the proposed controller performs much better than the others. Moreover, some empirical formulas for time domain characteristics of the reference model are numerically derived in terms of certain frequency domain specifications and time delay of the fractional reduced order model. The accuracy of these formulas is tested by simulations. The iso-damping, noise attenuation and load disturbance suppression performances of the proposed controller are also considered and compared with those of other related controllers.

Non-Asymptotic Confidence Sets for the Parameters of Linear Transfer Functions

Abstract: We consider the problem of constructing confidence sets for the parameters of input-output transfer functions based on observed data. The assumptions on the noise affecting the system are reduced to a minimum; the noise can virtually be anything, but in return the user must be able to select the input signal. In this paper a procedure for solving this problem is developed in the general framework of leave-out sign-dominant confidence regions. The procedure returns confidence regions that are guaranteed to contain the true transfer function with a user-chosen probability for any finite data set.

Apparatus for linearization of optic modulators using a feed-forward predistortion circuit

Abstract: A feed-forward predistortion circuit to provide improved linear response in optic modulators The circuit includes a non-linear element, an amplifier/delay means and a power combiner The non-linear element generates a first signal sin(X), where (X) is the input signal The amplifier/delay means generates a second signal 2(X) The first and second signals are combined in the power combiner to produce a modulating signal 2(X)-sin(X) which is fed to an optic modulator The modulating signal 2(X)-sin(X) compensates for the transfer function of the optic modulator which has a transfer function sin(X), thereby producing a linear output

The Bark bilinear transform

Abstract: Use of a bilinear conformal map to achieve a frequency warping nearly identical to the Bark scale is described. Because the map takes the unit circle to itself, its form is that of an allpass transfer function. Since it is a first-order map, it preserves the model order of rational systems. A direct-form expression for computing the optimal allpass coefficient as a function of sampling rate is developed, and a filter design example is presented.