Duplex filter operating as a change-over switch
First Claim
1. A filter comprising resonators, in which a first signal can pass in a first time slot between a first port and a third port and a second signal can pass in a second time slot between a second port and the third port, characterized in thatthe first signal path between the first and the third ports comprises a plurality of resonators,the second port is connected to one of said plurality of resonators in the first signal path, whereby a first subset of resonators lies between the first and the second ports, and a second subset of resonators lies between the second and the third ports forming the signal path between the second and the third ports,the resonators of one subset are switchable resonators, whose resonance frequencies can be shifted between two frequencies, the resonators of said one subset being connected to an external control means, such that on receipt of a first control signal from the control means the resonators of said one subset allow the signal to pass through substantially without attenuation, and on receipt of a second control signal from the control means the resonators of said one subset attenuate said signal.
2 Assignments
0 Petitions
Accused Products
Abstract
The invention discloses a three-port filter being able to connect alternately a receiver and a transmitter to a common antenna in a ratio system operating by the time division principle. The first signal path between the first and the third ports comprises all resonators (R1, R2, R3, R4). The second port is connected to one (e.g. R3) of the resonators in the first signal path, whereby a first subset (R1, R2) of resonators lies between the first and the second ports, and a second subset (R3, R4) of resonators forming the signal path between the second and the third ports lies between the second and the third ports. The resonators of either subset are switchable resonators, whose resonance frequencies can be shifted between two frequencies by an external control (Control). At the first control value of the control (Control) the resonators of this subset pass the RF-signal substantially without attenuation, and at the second control value they strongly attenuate said signal.
59 Citations
11 Claims
-
1. A filter comprising resonators, in which a first signal can pass in a first time slot between a first port and a third port and a second signal can pass in a second time slot between a second port and the third port, characterized in that
the first signal path between the first and the third ports comprises a plurality of resonators, the second port is connected to one of said plurality of resonators in the first signal path, whereby a first subset of resonators lies between the first and the second ports, and a second subset of resonators lies between the second and the third ports forming the signal path between the second and the third ports, the resonators of one subset are switchable resonators, whose resonance frequencies can be shifted between two frequencies, the resonators of said one subset being connected to an external control means, such that on receipt of a first control signal from the control means the resonators of said one subset allow the signal to pass through substantially without attenuation, and on receipt of a second control signal from the control means the resonators of said one subset attenuate said signal.
Specification