Multirate iterative learning control (ILC) systems have different sampling rates for feedback online loop and feedforward (or ILC) offline loop. The implementation of multirate ILC requires to downsample the signal first and, after processing, upsample the signal again. In the process of downsampling and upsampling, aliasing and imaging may occur and need to be handled properly. In this paper, ...

Multirate systems play an important role in modern telecommunication. Examples of their application are lter banks for image or speech coding, transmultiple-xers, sampling rate converters, and block processing systems. Usually they are designed under idealizing assumptions , neglecting wordlength eeects as well as the required coding between analysis and synthesis part of the multirate system. ...

In this paper, two multirate repetitive controllers are proposed, namely, repetitive intersample disturbance rejection (RIDR) and repetitive perfect tracking control (RPTC). First, in order to develop RIDR, multirate intersample disturbance rejection algorithm is reviewed which was proposed by authors for general digital control systems with restricted sampling frequency. Second, RPTC method is...

In this paper, a novel perfect tracking control method based on multirate feedforward control is proposed. The advantages of the proposed method are that: 1) the proposed multirate feedforward controller eliminates the notorious unstable zero problem in designing the discrete-time inverse system; 2) the states of the plant match the desired trajectories at every sampling point of reference inpu...

The paper discusses the issues of shift variance and cyclostationarity in multirate filterbanks as investigated in a series of articles by Til Aach. In its first part, the paper overviews the most important properties of multirate filterbanks such as perfect reconstruction, sampling rate conversion factors, number and type of subbands and subdivisions, orthogonality and bio-orthogonality, and f...

Because optical systems have a huge bandwidth and are capable of generating low-noise short pulses, they are ideal for undersampling multiband signals that are located within a very broad frequency range. We propose a new scheme for reconstructing multiband signals that occupy a small part of a given broad frequency range under the constraint of a small number of sampling channels. The scheme, ...

A new approach for designing a multirate output feedback control system using PID Controller, where the update interval of the control input is an integer multiple of the sampling interval of the plant output. The proposed method is designed by extending a conventional multirate output feedback control using the latest information of a plant. Hence, the proposed method can improve the control p...

In the present paper, we discuss a design method for a multirate system, in which the update interval of the control input is shorter than the sampling interval of the plant output. In this multirate system, the intersample output may oscillate between sampled outputs even if the sampled output converges to the reference input because the control input can be changed between sampled outputs. In...

This paper studies an intelligent digital control for nonlinear systems with multirate sampling. It is worth noting that the multirate control design is addressed for a given nonlinear system represented by Takagi–Sugeno (T–S) fuzzy models. The main features of the proposed method are that it is provided that the sufficient conditions for stabilization of the discrete-time T–S fuzzy system deri...