Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

FOUR-LEVEL AUTO SYNC DETECTION

IP.com Disclosure Number: IPCOM000009640D
Original Publication Date: 2000-Jan-01
Included in the Prior Art Database: 2002-Sep-06
Document File: 1 page(s) / 74K

Publishing Venue

Motorola

Related People

Joseph G. Markovich: AUTHOR [+2]

Abstract

In exisfing SECURBNET four level systems, the user must know, prior to SECURBNBT operation, if the system incurs a signal phase inversion. This must be known to allow proper data values to be decoded and placed into the range extension (REX) sync detectors. This invention removes the need to deter- mine if the systems inverts the inbound to outbound signal polarity while allowing proper RBX four level detection.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 50% of the total text.

Page 1 of 1

0 M MOTOROLA Technical Developments

FOUR-LEVEL AUTO SYNC DETECTION

by Joseph G. Markovich and Eric M. Giangrossi

ABSTRACT

  In exisfing SECURBNET four level systems, the user must know, prior to SECURBNBT operation, if the system incurs a signal phase inversion. This must be known to allow proper data values to be decoded and placed into the range extension (REX) sync detectors. This invention removes the need to deter- mine if the systems inverts the inbound to outbound signal polarity while allowing proper RBX four level detection.

THE PROBLEM

  In existing SECURENET systems that utilize four-level analog modulation, the system operator must predetermine the output polarity in relation to the input polarity of the system. The system operator must then program the subscriber unit via RSS according to the determined systems input to output polarity. This determination must be performed since existing REX sync detection performs detection on both polarities of an incoming two-level data signal, but does not perform proper inversion of four-level signals without predetermining signal polarity. The inverted four level data is not simply the complement of each bit in the four-level signal. Currently, the REX sync detection consists of two detectors, the first attempts to gain sync directly on the incoming

channel data, the second attempts to gain sync on the inverted incoming channel data, (i.e. a version of the signal in which each bit of the incoming data is inverted). The simple bit-by-bit inversion of the

incoming data signal, when four-level modulation is used, does not correctly invert the data signal since each level is...