Electronically variable equalizer
US4945311A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 29, 1988 |
| Grant date | Jul 31, 1990 |
| Priority date | — |
| Expiry date | Aug 29, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H11/1217
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
One or more active RC filter network stages of an electronically variable equalizer filter have R values which can be varied to maintain a substantially constant ratio of R values for each stage to vary the cutoff frequency of the equalizer filter while maintaining the relative shapes of the magnitude and phase characteristics of the equalizer filter. A control signal is generated to simultaneously vary the R values for the various network stages. The resistance value of the RC circuit of monostable multivibrator is controlled by control signal so that the multivibrator output pulse width is equal to a reference pulse width. The control signal is utilized to obtain the same R value for a number of other R values formed on a single substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.