Title:
FREQUENCY VARIABLE LC RESONANCE CIRCUIT
Document Type and Number:
Japanese Patent JPH01174107
Kind Code:
A
Abstract:
PURPOSE:To obtain a constant power pass band width even when the resonance center frequency is changed by using two or more types of materials with different permeability as a core varying the inductance of a variable coil. CONSTITUTION:The resonance circuit consists of the variable coil 1 and a capacitor 2. As the variable coil 1, two or more types of materials with different permeability such as brass and ferrite are in close contact to constitute the core for the variable coil. The sharpness Q of the resonance when a brass is put in the coil to increase the resonance frequency is made higher than the Q when the resonance frequency f0 is decreased with the ferrite in the coil. That is, the core material is selected so that the relation of (resonance frequency f0)/(sharpness Q of resonance) is always made constant. Thus, even when the resonance center frequency is changed, the power transmission band width is made nearly constant.
Inventors:
KOGA YASUHIRO
Application Number:
JP33260187A
Publication Date:
July 10, 1989
Filing Date:
December 28, 1987
Export Citation:
Assignee:
NEC CORP
International Classes:
H01F29/12; H03H5/02; (IPC1-7): H01F29/12; H03H5/02
Domestic Patent References:
| JP1071413B | ||||
| JPS5354801A | 1978-05-18 |
Attorney, Agent or Firm:
Ozeki Shinsuke