Tone detection
US6914979B2 · kind B2 · utility
6Cited by
4References
2Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 25, 2001 |
| Grant date | Jul 5, 2005 |
| Priority date | — |
| Expiry date | Sep 2, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/005
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A DFT is used to compute the magnitude and phase of the frequencies desired to be detected in a frame of sampled data by performing 2 dot products for each such frequency. The two dot products are calculated using the samples in the frame and an equal number of equally spaced cosine and sine coefficients for each frequency to be detected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.