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Digital Spectrum Spreading Method

IP.com Disclosure Number: IPCOM000091849D
Original Publication Date: 1968-Jun-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Riso, V: AUTHOR

Abstract

Spreading of a signal spectrum requires three steps. These are a rectification, a compression, and an increasing of the number of zero crossings by use of a W-network. These operations are performed by use of PCM log analog-to-digital converter 1, decoding network 2 and PCM linear digital-to-analog converter 3.

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Digital Spectrum Spreading Method

Spreading of a signal spectrum requires three steps. These are a rectification, a compression, and an increasing of the number of zero crossings by use of a W-network. These operations are performed by use of PCM log analog-to-digital converter 1, decoding network 2 and PCM linear digital-to- analog converter 3.

The input-output characteristic of converter 1 is shown. It is assumed converter 1 is a six-bit PCM log analog-to-digital device. The data format is s , C1, C2, b, c, d, where s is the sign, C1 and C2 are two bits which characterize the area A, B, C or D, where the input signal is placed, and b, c, and d are three bits which determine the level into the areas.

With converter 1, the compression is realized by its input-output characteristic. Rectification is effected by suppressing sign s. Network 2 realizes the increasing of the number of zero crossings of the axis. Converter 3 gives the spreaded spectrum in an analog form. The W characteristic of network 2 is shown.

Four areas A, B, C, D are determined and correspond respectively to the four areas A, B, C, D of converter 1. The output data format is S, alpha, beta, and gamma, where S is the sign and alpha, beta, and gamma are three bits giving the level into the areas.

The truth table shows the relation between C1, C2, b, c, and d and S, alpha, beta and gamma.

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