Lucent Technologies Inc.

At&t Bell Laboratories

Christopher James Chrin

Meyer Joseph Zola

Kevin Eugene Dombkowski

Apparatus, and a method for flexibly switching telecommunication signals. A plurality of input bit streams are connected to a telecommunications switching network fabric element comprising a microprocessor system including memory. The microprocessor system, under program control, performs switching and protocol conversion functions on the input streams in order to generate output streams. Advantageously, a single element is able to concurrently switch input signals in a variety of protocols, including circuit switching protocols, such as Pulse Code Modulation (PCM), and packet switching protocols, such as Asynchronous Transfer Mode (ATM) protocols and Internet Protocol, (IP). Where desirable, the microprocessor system can also control the protocol conversion of input signals in one protocol to output signals in another protocol.

Flexible telecommunications switching network

Apparatus, and a method for switching digital signals of different protocols in a large switching network. Signals and different protocols are encapsulated in a common protocol by a set of input modules. The signals in the common protocol are then switched by a large central stage to a plurality of output modules, which then generate signals in the correct protocol. Narrow-band signals are converted into broadband signals, so that the central stage switches only broadband signals. This simplifies the design of the central stage, while still making it possible to have a very large and economical central stage switch. Advantageously, this arrangement allows a single large switch to switch large quantities of traffic in a plurality of protocols.

Large combined broadband and narrowband switch

An enhanced form of time switch. Serial bit streams received in input buffers are stored in parallel under program control in the cache of a pipe lined microprocessor. The microprocessor, under program control, then rearranges the received time slots and feeds them in parallel to output buffers from which serial bit streams are generated. Advantageously, program control is used to flexibly control the various functions of different time switches without requiring a change in the hardware.

Enhanced telecommunications switching unit

A method of generating the digital representation of a sine wave. A digital signal processor is used to generate the sample digital values, spaced at period T, of a sine wave of frequency F, using the value of the previous sample, e, the corresponding value of cosine, f, and two constants, c=sin2.pi.FT and d=cos2.pi.FT. The next value of sine, S=ed+cf; the value of the corresponding cosine, C=df-ce. The magnitude of c and d are rounded up so that c.sup.2 +d.sup.2 .gtoreq.1. Any calculated values of S or C which exceed unity in magnitude are limited to a magnitude of unity. This limiting operation accomplishes the normalization operation necessary to avoid exponential build-up due to accumulated round-off errors, and does so more efficiently than was previously possible. Sine waves with a 50 dB signal to noise ratio have been generated using this method.

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Lisle, IL, United States of America

Christopher James Chrin