Thursday, 22 November 2007

Verizon chooses Nortel for new European optical network

LONDON -- Nortel will deploy a new ultra long haul optical network across Europe to enable Verizon to meet the increasing network demands of its service provider and large enterprise customers and deliver high-bandwidth services like video and online gaming.

The multi-million dollar deal includes a Nortel Metro Ethernet Networking solution that will support Verizon’s planned introduction of 10G services and the emerging 40G services that may be introduced in the future.

“Verizon has taken a bold, forward-looking approach to building out its network,” said Philippe Morin, president, Metro Ethernet Networks, Nortel. “It provides the ability to deliver the bandwidth capacity that service providers and businesses require today and the critical ability to evolve seamlessly to 40G when needed.”

“Of course the true beneficiaries are the end users who will gain unrestricted access to new, high-bandwidth services and applications, such as video, advanced business services and multimedia communications. This development also supports the coming megatrend of Hyperconnectivity, where every device that should be connected to the network, will be connected.”

The new network will carry more than 80% of Verizon’s European network traffic and will be deployed across multiple countries, including the United Kingdom, France, Belgium, Germany and the Netherlands.

In addition to providing increased bandwidth, the new next-generation, ultra-long haul optical network allows Verizon to reduce costs as it simplifies network operations and requires less equipment.

Nortel is the sole supplier of the Adaptive, All Optical Solution and Nortel Global Services is assisting with the deployment to provide a turnkey solution for Verizon that will include integration into existing management systems and Network Operation Center facilities.

The new Verizon optical network is based on the Optical Multiservice Edge 6500, a next-generation optical convergence platform. The solution also features Nortel's unique electronic Dynamically Compensating Optics (eDCO), which simplifies networking by extending 40G wavelengths over thousands of kilometers without requiring dispersion compensation modules, greatly simplifying the network.

Verizon is also using the Common Photonic Layer (CPL) which will enable migration to a more agile, adaptive, all optical intelligent network. Nortel’s Reconfigurable Optical Add/Drop Multiplexing (ROADM) technology is also included in the solution to make it easy to add and route new services, resulting in a more cost-effective, reliable infrastructure. In addition, the Nortel Optical Network Manager will provide the required operations, administration and management for the new network.

Sunday, 18 November 2007

Pitch Spelling Algorithms

Pitch Spelling Algorithms
Pitch spelling algorithm is the process of assigning appropriate pitch names that are consistent with the key context to numeric representations of pitch, such as, MIDI or pitch class numbers.

They introduce two new notions of approximate matching with application in computer assisted music analysis and also present algorithms for each notion of approximation: for approximate string matching and for computing approximate squares.

-Chew and Chen
The algorithm is spiral array model.

Sunday, 11 November 2007

Introduction to Acquisition Process

1. Serial search
-The algorithm tests the cells one by one.
-The cell corresponds to the correct code-phase and Doppler of the acquired signal within a given resolution.
2. Parallel search
In this architecture the test statistics are generated over the entire search.
3. Hybrid
With the hybrid search strategy the whole search is divided into a number of test regions each consisting of a few cells.

Introduction to Fourier Optics

Aperture effect
When the incident wave goes through an aperture, the observed field is the combination. If a distant object is viewed through a small circular aperture that is placed close to the eye, there is an apparent "shadowing" of the center of the viewed image, while the inner perimeter of the aperture is bright.

What is Fourier Optics?(quoted from )
Fourier optics describes the propagation of light using Fourier analysis. It can be used to describe Fresnel and Fraunhofer diffraction. The Fraunhofer diffraction pattern is the Fourier transform of the diffracting object.
Fresnel diffraction describes the diffracted light field a large distance away from the object compared to the wavelength of light, but not so large the curvature of the wavefront can be neglected. Fraunhofer diffraction describes the diffracted light field a large distance away from the object such that the curvature of the wavefront can be neglected.
Possible uses are:
• Describing image formation
• Modelling the aberrations of an optical system
• Studying the performance of a lens
• Modelling diffraction patterns and light propagation
• Optical signal processing
• Optical computing