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    Antenna switch circuit
    8.
    发明专利
    Antenna switch circuit 未知

    公开(公告)号：GB2404797A

    公开(公告)日：2005-02-09

    申请号：GB0318612

    申请日：2003-08-08

    Applicant: MOTOROLA INC

    Inventor： FRIEDLANDER HAIM ,  LUZZATTO ARIEL ,  SCHWARTZMAN ZALMAN ,  SHIRAZI GADI

    IPC: H04B1/40 ,  H04B1/48 ,  H02H1/04 ,  H02H9/04

    Abstract: An antenna switch circuit 300 for use in an RF transceiver is connected to a transmitter circuit 103, a receiver circuit 102, and an antenna 101. The switch circuit 300 selectively connects the transmitter 103 and the receiver 102 circuits to the antenna 101. Electrically-controlled devices, such as PIN diodes D1-4, are arranged to perform the switching and to prevent electrostatic discharges of either positive or negative polarity from reaching the transmitter 103 or receiver 102 circuits. Two pairs of PIN diodes D1,3, D2,4 may each be connected so that they have opposed unipolar conductivities. A dc voltage may be applied through an RF-isolating component RFC1, 2 to control the electronically-controlled devices D1-4. The antenna switch circuit 300 may be included in an RF communications apparatus, such as a mobile or fixed radio terminal, or in mobile telephones, mobile radios, or data communications terminals. In a further embodiment the antenna switch circuit may also protect from excessive RF power entering the antenna.

    Isolator device for RF radiators
    9.
    发明专利
    Isolator device for RF radiators 未知

    公开(公告)号：GB2382231A

    公开(公告)日：2003-05-21

    申请号：GB0126222

    申请日：2001-11-01

    Applicant: MOTOROLA INC

    Inventor： SCHWARTZMAN ZALMAN ,  GROSSMAN OVADIA ,  SHIRAZI GADI

    IPC: H01P3/08 ,  H05K9/00

    Abstract: An electrical isolator (10) for suppressing interference currents in an RF radiating device comprises a conducting elongate element (M3) for conducting RF signals, and further conductors (M2, M4) surrounding but not electrically connected to the elongate element, with further outer conductor layers surrounding the conductors (M2, M4). The layers (M2, M4) and outer conducting layers are connected to each other at one end of the isolator and grounded via conductors (18, 20) to form a shield against electromagnetic interference. The elongate element (M3) of the isolator is used to connect output signal conductor (12) of a transmitter to antenna (16). The conducting element and layers are formed as metal films on insulating substrates which are joined together.

    10.
    发明专利
    未知

    公开(公告)号：MX9304003A

    公开(公告)日：1994-04-29

    申请号：MX9304003

    申请日：1993-07-02

    Applicant: MOTOROLA INC

    Inventor： RAPOPORT GIL ,  RAMON EYTAN ,  SHIRAZI GADI ,  SCHWARTZMAN ZALMAN ,  KASHTAN AHARON ,  GERSHKOVICH IZIDOR

    IPC: H04B1/38 ,  H04M1/60 ,  H04M1/725 ,  H04M19/04 ,  H04Q7/32 ,  H04M1/00

    Abstract: FIGS. 2 and 3 illustrate communications devices (30) that are operable in both a radio dispatch mode and a telephone interconnect mode. To mitigate the problem of a relatively high level audio signal from being unexpected broadcast from an ear-piece of the device (30) when the ear-piece is proximally located with an ear of a user of the device, the communications device (30) is arranged to ensure that, at least during an initial period of operation in either of the two operating modes, audio signals of relatively high level do not originate from the ear-piece, thereby preventing a change in audio power output from the ear-piece that may potentially cause damage to the hearing of a user of the radio communications device.

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