公开(公告)号：JP2003234641A

公开(公告)日：2003-08-22

申请号：JP2003007039

申请日：2003-01-15

Applicant: LUCENT TECHNOLOGIES INC

Inventor： FRATTI ROGER A ,  LOPATA DOUGLAS D

IPC: H03H19/00

Abstract: PROBLEM TO BE SOLVED: To implement circuits with switched capacitors, such as a ladder filter, so that they can be continuously tuned. SOLUTION: In an integrated circuit with the switched capacitor, the switched capacitor is implemented as a DC-isolated variable capacitor. The DC-isolated variable capacitor is implemented as a T-structure having three capacitors in which one of the three capacitors is implemented with a buffer amplifier configured to receive a control signal and to apply a buffered control signal to an active device having a capacitance that is dependent on the level of the buffered control signal. In one embodiment, the capacitor C 2 of the T-structure is implemented using a voltage-controlled buffer 402 and a varactor diode 404. The buffer 402 is a high-impedance output buffer that provides isolation and preconditions and/or scales a control voltage. COPYRIGHT: (C)2003,JPO

公开(公告)号：JP2000059179A

公开(公告)日：2000-02-25

申请号：JP20518299

申请日：1999-07-19

Applicant: LUCENT TECHNOLOGIES INC

Inventor： FRATTI ROGER A ,  LOPATA DOUGLAS D

IPC: H03H19/00

Abstract: PROBLEM TO BE SOLVED: To continuously adjust a circuit provided with a switched capacitor like a ladder type filter. SOLUTION: For this integrated circuit provided with the switched capacitor, the switched capacitor is realized as a DC insulation variable capacitor. The DC insulation variable capacitor is realized as a T structure provided with three capacitors and one of the three capacitors is realized together with a buffer amplifier. The buffer amplifier receives control signals and inputs buffered control signals to an active device provided with capacitance depending on the level of the buffered control signals. For instance, the capacitor C2 of the T structure is realized by using a voltage control buffer 402 and a varactor diode 404. The buffer 402 is a high impedance output buffer for providing insulation and adjusting or increasing/decreasing a control voltage beforehand.

公开(公告)号：JP2000252710A

公开(公告)日：2000-09-14

申请号：JP2000048693

申请日：2000-02-25

Applicant: LUCENT TECHNOLOGIES INC

Inventor： BOWEN JOHN WAYNE ,  FRATTI ROGER A ,  WEST MELVIN

IPC: H03H7/42 ,  H01P5/10

Abstract: PROBLEM TO BE SOLVED: To improve a device for actualizing a transmission line balance-to- unbalance transformer which supplies a single end output signal from a couple of difference input signals by crossing and coupling components of a couple of transmission line signal couplers tandem. SOLUTION: The transformer is composed of 1st and 2nd transmission line signal couplers which have coupling characteristics, respectively, and those couplers are electrically insulated from each other. Those couplers include transmission line elements which are coupled tandem with each other through specific signal phase adjustment and total improved coupling characteristics are provided for the coupling characteristics of the 1st and 2nd signal couplers. For example, this transformer has a coupler C1 connected to a couple of input ports P1 and P2, which are coupled with input ends 1 and 5 of microwave transmission line elements a1 and a2. The output ends 2 and 6 of the elements a1 and a2 are crossed and coupled tandem with the input ends 7 and 3 of transmission line elements b1 and b2 by electric connections 10 and 11.