Efficient Multirate Filtering

Efficient Multirate Filtering

Ljiljana D. Milic (University of Belgrade, Serbia)
DOI: 10.4018/978-1-60566-026-4.ch205
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Abstract

A multirate filter can be defined as a digital filter in which the input data rate is changed in one or more intermediate points. With the efficient multirate approach, computations are evaluated at the lowest possible sampling rate, thus improving the computational efficiency, increasing the computation speed, and lowering the power consumption. Multirate filters are of essential importance for communications, image processing, digital audio, and multimedia. The role of multirate filtering in modern signal processing systems is threefold: Firstly, they are used whenever there is a need to preserve the signal properties when connecting two systems operating at different sampling rates. Secondly, multirate techniques are used for constructing filters with stringent spectral constraints that are very difficult, even impossible, to be solved otherwise. Thirdly, multirate filters are used in constructing multirate filter banks.
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Introduction

The purpose of this article is to contribute to the definition of the still emerging strategic concept of e-societal management (e-SM) as a key component of the information society (IS). It is a continuation of articles published in the Encyclopedia of Digital Government (Antiroikko, 2006; see also, Costake, 2008a, 2008b) which describe the concepts of:

  • (1)

    e-government (e-Gvt) as a set of e-services provided by the public administration (i.e., executive authority) to citizens and organizations, and

  • (2)

    e-governance (e-G) as including also the set of e-services provided by the judicial and legislative authorities of the state.

The two quoted chapters contain the historical perspectives mainly between the mid-1990s (e.g., G7 Conference on Information Society, 1995) and the mid 2000s (e.g., the EU’s i2010 Program, 2006). The above definition of e-G may be interpreted also as equivalent to the e-SM at the country level and below, provided that the actions of the three authorities converge to assure continuous and sustainable socio-economic development. On the other hand, the new century started with increased global threats and also opportunities (e.g., the development of the IS). Both suggest the importance of the societal management, as well as the difference between enterprise management, which aims to achieve performance within a given national and international societal environment, and societal management, which aims to assure the societal environment best supporting developments of the economy and civilization.

It follows that the historical development of e-SM is connected to the rather slow evolution of SM and the rapidly developing IS, including e-Gvt and e-G. Its start can be considered the UN General Assembly’s Declaration on Computer and Development (UN, 1968), followed by the UN’s World Summit for the IS (e.g., WSIS, 2005), which adopted requirements for national and international e-SM (implicitly addressed). E-procurement for public acquisitions, the “Trans-European Administration Network” recommended for the EU by Bangemann et al. (1994), and the start of the Single Euro Payment Area project in 2002 (see SEPA, 2007, which contains complete chronology and content) are examples of other relevant milestones. E-SM is a concept built on those of socio-economic system (SES) and societal management. Many opinions were expressed.

This article begins by sketching a model of the socio-economic system as a foundation; selects, with the risk of being subjective, a number of relevant positions taken by individual institutional and authors; describes e-SM and its associated issues and trends; and proposes conclusions.

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Background

The general model of the global SES, suggested in Figure 1, includes natural resources (a component of the natural system) and the human activities system (HAS), layered above the natural system. In the absence of the HAS, the natural system was stationary, its biologic components being in a dynamic equilibrium (their growth and levels limited by the available resources). The HAS also transforms data into information, and information into knowledge, thus accumulating experience. It also enforces the concept of ownership, developing the economic activity. Some frequently mentioned risks and issues for the global SES are mentioned in Table 1.

Figure 1.

Layered model of the global SES (Legend: flows of matter/energy/products/services, information, financial means)

Key Terms in this Chapter

FIR Filter: A finite impulse response digital filter.

Multistage Filtering: Cascade of filters and decimators (interpolators and filters).

IIR Filter: An infinite impulse response digital filter.

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