Reception techniques for improving intelligibility of an audio frequency signal
US4044205A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 11, 1975 |
| Grant date | Aug 23, 1977 |
| Priority date | — |
| Expiry date | Mar 11, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G11/00
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The reception technique for improving intelligibility of an audio frequency signal containing interference and wanted speech signals by selecting a narrow section of the frequency band of the audio frequency signal in which the interference is the least, and filtering out this section from the rest of the band. A control signal is then derived by utilizing the changing value of the mean amplitude of the filtered section, to amplitude modulate the interference, thereby eliminating noise between speech syllables. One embodiment involves deriving a control voltage proportional to the True-Signal Voltage, such that compressor-gain increases when there is only noise-signal at the input, (i.e., Zero True-Signal and thus Zero Control Voltage), which in turn over-drives a limiter to clip the input noise - signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.