Tone signal detecting method and tone signal detector
US6687368B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 17, 2000 |
| Grant date | Feb 3, 2004 |
| Priority date | — |
| Expiry date | Mar 17, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q1/46
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method for detecting a tone signal includes determining a correlative value of an input signal obtained for each frame of a predetermined length, determining an estimating expression that represents an output power of a second order FIR band elimination filter that uses the correlative value of the input signal as an input and a frequency thereof as a parameter, determining a frequency at which a minimum value of the estimating expression is obtained, determining a prediction gain of the FIR band elimination filter at the determined frequency, and determining that the input signal is a tone signal if a value of the determined prediction gain exceeds a preset threshold value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.