Method for tuning a filter circuit
US4272743A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 20, 1979 |
| Grant date | Jun 9, 1981 |
| Priority date | — |
| Expiry date | Apr 20, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J3/08
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of tuning a trap circuit to a desired frequency is provided. A constant amplitude signal is applied to the trap circuit in a progression of successively different frequency increments. The frequency increments cover a frequency range including the desired frequency. The amplitude of the signal, as modified by the trap circuit is detected and stored at each of the different frequency increments. Successive ones of the stored amplitude values are compared until an amplitude difference is found which is greater than a predetermined minimum difference and is of a polarity indicative of an increase in amplitude with the progression, and is a successor of an amplitude difference which is greater than the predetermined minimum difference and of a polarity indicative of a decrease in amplitude with the progression. The frequency at which the inflection point occurs, as indicated by the two-named amplitude differences, represents the null frequency of the trap circuit. The trap circuit is then tuned to align the null frequency with the desired tuning frequency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.