Transmitting data on the phase of speech
US4495620A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 1982 |
| Grant date | Jan 22, 1985 |
| Priority date | — |
| Expiry date | Aug 5, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M11/064
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a means for achieving simultaneous transmission of data and speech with only a minimal expansion of the bandwidth of the speech signal. A Fourier transform (14) is performed on the speech signal and a predetermined number of phase components are replaced with data (d(n)) in an appropriate form. The number of phase components replaced with data is determined by approximately classifying the speech (16) as either "silence", no data inserted; "unvoiced" speech, M phase components convey data; and "voiced" speech, J phase components convey data; where J is less than M, and M is not greater than the number of phase components in the message band of the speech signal. An inverse Fourier transform (22) is subsequently performed on the combined data and speech signal. The combined message signal (G(t)) will comprise approximately the same bandwidth as the original speech signal, by virtue of the frequency domain insertion of the data into the speech. At the receiver the signal is inspected and a classifier (38) determines if data is embedded in the received signal. If data is deemed embedded, a Fourier transformation is performed, the data carrying phase co…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.