Noise reduction system having series connected low and high frequency emphasis and de-emphasis filters
US4363007A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 1981 |
| Grant date | Dec 7, 1982 |
| Priority date | — |
| Expiry date | Apr 23, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G9/025
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In a noise reduction system including a compressor and an expander having a complementary frequency response characteristic to the frequency response characteristic of the compressor, the compressor includes a high frequency emphasis variable frequency filter and a low frequency emphasis variable gain filter which are connected in a series circuit between input and output terminals and which respectively vary their parameters in response to the respective high and low frequency components of the compressor output. The expander includes a high frequency de-emphasis variable frequency filter and a low frequency de-emphasis variable gain filter which are connected in a series circuit between input and output terminals and which respectively vary their parameters in response to the respective high and low frequency components of the expander input.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.