Tone detection process and device for implementing said process
US4782523A · kind A · utility
24Cited by
1References
13Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 27, 1987 |
| Grant date | Nov 1, 1988 |
| Priority date | — |
| Expiry date | Apr 27, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q1/457
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The process is made to detect a received tone including at least one single predetermined frequency, within a signal encoded using block coding and Linear Prediction Coding techniques providing auto-correlation coefficients R(i) and direct form coefficients a(i). The process is based upon Fourier Transform computations over the successive blocks of a(i)'s, with table look up tone identification, further confirmed upon R(i)'s stationarity detecting.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.