Bandwidth expansion

Bandwidth expansion

Bandwidth expansion is a technique for widening the bandwidth or the resonances in an LPC filter. This is done by moving all the poles towards the origin by a constant factor gamma. The bandwidth-expanded filter A'(z) can be easily derived from the original filter A(z) by:

:A'(z) = A(z/gamma)

Let A(z) be expressed as:

:A(z) = sum_{k=0}^{N}a_kz^{-k}

The bandwidth-expanded filter can be expressed as:

:A'(z) = sum_{k=0}^{N}a_kgamma^kz^{-k}

In other words, each coefficient a_k in the original filter is simply multiplied by gamma^k in the bandwidth-expanded filter. The simplicity of this transformation makes it attractive, especially in CELP coding of speech, where it is often used for the perceptual noise weighting and/or to stabilize the LPC analysis. However, when it comes to stabilizing the LPC analysis, lag windowing is often preferred to bandwidth expansion.

References

P. Kabal, "Ill-Conditioning and Bandwidth Expansion in Linear Prediction of Speech", "Proc. IEEE Int. Conf. Acoustics, Speech, Signal Processing", pp. I-824-I-827, 2003.


Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • bandwidth expansion ratio — juostos išplėtimo santykis statusas T sritis radioelektronika atitikmenys: angl. bandwidth expansion ratio vok. Bandverbreiterungszahl, f rus. коэффициент расширения полосы, m pranc. rapport d étalement de la largeur de bande, m …   Radioelektronikos terminų žodynas

  • Global Information Grid-Bandwidth Expansion — The Global Information Grid Bandwidth Expansion (GIG BE) Program was a major United States Department of Defense (DOD) net centric transformational initiative executed by DISA. GIG BE created a ubiquitous bandwidth available environment to… …   Wikipedia

  • Expansion card — Example of a PCI Digital I/O Expansion Card. The expansion card (also expansion board, adapter card or accessory card) in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard or backplane to… …   Wikipedia

  • GIG-BE — Global Information Grid Bandwidth Expansion (Computing » Networking) Global Information Grid Bandwidth Expansion (Governmental » US Government) Global Information Grid Bandwidth Expansion (Governmental » Military) …   Abbreviations dictionary

  • Global Information Grid — The Global Information Grid (GIG) is an all encompassing communications project of the United States Department of Defense. It is defined as the globally interconnected, end to end set of information capabilities,associated processes, and… …   Wikipedia

  • Global Information Grid-Enterprise Services — GIG Enterprise Services The Defense Information Systems Agency s (DISA) Global Information Grid Enterprise Services Engineering (GE) directorate plans, engineers, acquires and integrates joint, interoperable, secure global net centric solutions… …   Wikipedia

  • Defense Information Systems Agency — Seal …   Wikipedia

  • By Light — was founded in 2002 by a group of retired senior military officers and telecommunications industry veterans. By Light is a Service Disabled Veteran Small Business specializing in IT engineering services. Most business is with U.S. Defense,… …   Wikipedia

  • Code excited linear prediction — (CELP) is a speech coding algorithm originally proposed by M.R. Schroeder and B.S. Atal in 1985. At the time, it provided significantly better quality than existing low bit rate algorithms, such as RELP and LPC vocoders (e.g. FS 1015). Along with …   Wikipedia

  • Global Information Grid — Vue schématique du Global Information Grid Le Global Information Grid (GIG) est un réseau de transmission et de traitement de l information maintenu par le Département de la Défense des États Unis (DoD)[1]. De façon plus descriptive, le GIG est …   Wikipédia en Français

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”