Patent · US Expired

Tone detector for use in a modem

US6711205B1 · kind B1 · utility

2Cited by
86References
41Claims
0Family size

Assignee

Inventor

Key dates

Filing dateSep 25, 1998
Grant dateMar 23, 2004
Priority date
Expiry dateSep 25, 2018

Classification

  • Technology area (CPC H)Electricity
  • CPC primaryH04Q1/44
  • WIPO fieldTelecommunications
  • WIPO sectorElectrical engineering

Abstract

A tone detector for a modem detects the presence of a tone, such as that sent during a retraining request, using a complex adaptive FIR filter of the form 1−z−1. The filter will detect the tone regardless of symbol rate.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.