Automatic noise limiter
US4042883A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 25, 1976 |
| Grant date | Aug 16, 1977 |
| Priority date | — |
| Expiry date | Mar 25, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G3/345
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The output from a peak detector of a conventional radio receiver includes a recovered audio signal and a DC level. The disclosed noise limiter processes the detector output through both low pass and high pass filters. The low pass filter produces a DC signal representative of both the detector DC level and the recovered audio signal level. The high pass filter passes only the recovered audio signal. A semiconductor diode connects between the filter outputs, and the output of the noise limiter. For peak detector levels at, or below the 100% modulation level the diode is forward biased and passes the audio signal to the noise limiter output for further receiver processing. Peak detector levels exceeding 100% modulation, such as noise, reverse bias the diode whereby the audio signal is blocked from subsequent receiver stages.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.