Bandpass filter with an active element
US4409557A · kind A · utility
29Cited by
8References
19Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Apr 23, 1981 |
| Grant date | Oct 11, 1983 |
| Priority date | — |
| Expiry date | Apr 23, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H11/1291
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An amplifier including an in phase feedback signal to therefore exhibit negative resistance is receptive of an input alternating signal which includes a frequency F. The output of the amplifier is coupled to a resonator adjusted to a center frequency F and having undesirable resistance which is offset by the negative resistance of the amplifier. The resonator includes an inductor and adjustable capacitor arranged either in series or in parallel with the amplifier to therefore change the value of F.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.