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

ANALOG CONTEXT-SENSITIVE COMPARATOR

IP.com Disclosure Number: IPCOM000008504D
Original Publication Date: 1997-Dec-01
Included in the Prior Art Database: 2002-Jun-18
Document File: 1 page(s) / 76K

Publishing Venue

Motorola

Related People

Keith Eberlein: AUTHOR [+3]

Abstract

Normally in a wide-area private land mobile system, the voice users are "polite"-only one user talks at a time. However, occasionally multiple users will key up and begin talking at roughly the same time. Existing analog comparators, whose job is best signal selection, do not realize that they are dealing with more than one signal source, let alone more than one copy of a signal. Because compara- tors will switch signals as signal qualities change, the result in this situation is that it may altogether change which user's audio gets routed.

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

ANALOG CONTEXT-SENSITIVE COMPARATOR

by Keith Eberlein, Joel F. Klein and Matt Laswell

PROBLEM

  Normally in a wide-area private land mobile system, the voice users are "polite"-only one user talks at a time. However, occasionally multiple users will key up and begin talking at roughly the same time. Existing analog comparators, whose job is best signal selection, do not realize that they are dealing with more than one signal source, let alone more than one copy of a signal. Because compara- tors will switch signals as signal qualities change, the result in this situation is that it may altogether change which user's audio gets routed.

  Instead of this non-deterministic and undesir- able behavior, it is proposed that the comparator stick with the signal it originally selected. The concept of context groups, or groups comprised of multiple copies of the same signal is well-known in digital comparators. The comparator's inputs are divided into groups that are thought to be from the same subscriber, and then only one of these groups is selected to be voted and then routed. The problem in the case of an analog comparator is how to deter- mine which analog inputs belong to which context groups.

SOLUTION

  The context group management is divided into two phases. The first phase is at the beginning of the call, when no previous information about the signals is available. The second phase is during the call, as the user(s) may roam, causing the profile of signals from each satellite receiver to change dramatically.

During the first phase, current analog methods are used to pick an initial signal to vote based on

absence of noise and other factors. The comparator re...