Patent EP0570184A1 successfully refreshed from Google Patents.
EP0570184A1
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EP
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A filter used as transmit-receive switch
Assignee: Pulse Finland Oy
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Filing: 1993-05-10
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Granted: —
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Expires: 2013-05-10
Abstract
Abstract The invention discloses a three-port filter being able to connect alternately a receiver and a transmitter to a common antenna in a radio 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.
Inventors
- 👤 Tapio Takkalo
- 👤 Aimo Turunen
- 👤 Pauli Nappa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 17:40
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/54; H04B1/56; H04B1/44; H04B1/48
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
197 words
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 resistors, - the second port is connected.to one of said plurality of resonator 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 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 subset attenuate said signal.
Claim 2
Dependent Claim
32 words
A filter according to claim 1, wherein that the frequency of the first and second signals is substantially equal to the operating frequency of a system with which the filter is used.
Claim 3
Dependent Claim
34 words
A filter according to claim 2, wherein the control signal of the control means during the first time slot controls the resonators of the first subset to pass a signal at the operating frequency.
Claim 4
Dependent Claim
47 words
A filter according to claim 2 or claim 3, wherein that the resonant frequencies of the resonators between the first and the third ports and the couplings between the resonators are dimensioned so that the filter thus formed has a low attenuate function at the operating frequency.
Claim 5
Dependent Claim
38 words
A filter according to any of claims 2 to 5, wherein that the control value from the control during the second time slot controls the resonators of the first subset to attenuate a signal at the operating frequency.
Claim 6
Dependent Claim
30 words
A filter according to claim 5, wherein that the control signal of the control means shifts the resonance frequencies of the first subset of resonators away from the operating frequency.
Claim 7
Dependent Claim
38 words
A filter according to claim 1, wherein that the first and second signals have a different frequency, and that the control means during the.first time slot controls the resonators of the second subset to transmit the first signal.
Claim 8
Dependent Claim
42 words
A filter according to claim 7, wherein that the frequencies of the resonators between the first and the third ports and the couplings between them are dimensioned so that the filter formed by them transmits at the frequency of the first signal.
Claim 9
Dependent Claim
30 words
A filter according to claim 7 and 8, wherein that the control means during the second time slot controls the resonators of the second subset to transmit the second signal.
Claim 10
Dependent Claim
25 words
A filter according to claim 9, wherein that the control means offsets the resonance frequencies of the first subset of resonators by an exact amount.
Claim 11
Dependent Claim
62 words
Filter according to any previous claim, wherein that the filter is the antenna filter of a radio apparatus and that the first port is connected to the receiver branch, the second port is connected to the transmitter branch and the third port is connected to the antenna, whereby the filter operates as a change-over switch between the first and the second ports.
References Cited (Backward Citations)
EP0446050A2
Cited
FR2664766A1
Cited
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