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US 4,287,605 AGranted
Directional filter for mixers, converters and the like
AssigneeMotorola, Inc.
InventorMichael Dydyk
Life of this patent
Estimating the term…
Abstract
First and second directional couplers each having a primary arm, a through arm and two secondary arms with a resonant circuit constructed to include the two secondary arms of each directional coupler. The directional filter forms a four port device with signals of a first frequency being applied to the first port and coupled to the fourth port by the resonant circuit, and signals applied to the third port being conveyed directly to the first port. Signals other than those at the first frequency are not coupled between the first and fourth ports.
Claims9
A directional filter comprising:
- (a) a first transmission line having an input for signals of a first frequency, f.sub.1 ;
- (b) a second transmission line having an input for signals of a second frequency, f.sub.2, and an output;
- and
- (c) coupling means formed of a third transmission line in a closed loop of a length determined by ##EQU3## coupled to said first and second transmission lines and tuned to provide substantially maximum coupling of the first frequency signals from the first to the second transmission lines and substantially minimum coupling of the second frequency signals from the second to the first transmission lines.
1 more element
Dependencies are inferred from the claim text.