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    LOCAL OSCILLATOR LEAKAGE CANCELLATION CIRCUIT
    1.
    发明专利
    LOCAL OSCILLATOR LEAKAGE CANCELLATION CIRCUIT 失效

    公开(公告)号：JP2000049631A

    公开(公告)日：2000-02-18

    申请号：JP19787999

    申请日：1999-07-12

    Applicant: LUCENT TECHNOLOGIES INC

    Inventor： KANNELL GEORGE KENNETH ,  MYER ROBERT EVAN ,  SREENATH KRISHNAMURTHY

    IPC: H03C3/00 ,  H03C1/06 ,  H03D7/00 ,  H04B1/04 ,  H04B1/26

    Abstract: PROBLEM TO BE SOLVED: To suppress the transmission of unrequired signals by generating signals proportional to the leakage signal level of the local oscillator of a radio frequency converter or the like and canceling leakage by a feedback correction loop. SOLUTION: Composite signals generated by input IF signals and signals LO from the local oscillator 10 in a frequency converter 20 are inputted to a detection circuit 30, an error voltage proportional to an unrequired signal level is generated and fed back to the frequency converter 20 and the action of canceling unrequired signals is performed. The error voltage is directly supplied to the converter in the case that the converter 20 is provided with one input voltage like a mixer and it is supplied through a null circuit 40, DC balance is adjusted so as to keep an LO level low and control signals are generated in the case that plural DC connection IF input ports are provided like a quadrature modulator. Also, the detection circuit 30 adds sine wave and cosine wave output, takes an absolute value and generates error signals and thus, an excellent operation is obtained at a low cost.

    2.
    发明专利
    未知

    公开(公告)号：DE69923632T2

    公开(公告)日：2006-01-05

    申请号：DE69923632

    申请日：1999-07-06

    Applicant: LUCENT TECHNOLOGIES INC

    Inventor： KANNELL GEORGE KENNETH ,  MYER ROBERT EVAN ,  SREENATH KRISHNAMURTHY

    IPC: H03C3/00 ,  H03C1/06 ,  H03D7/00 ,  H04B1/04 ,  H04B1/26

    Abstract: A method for reducing the level of an undesired signal, generated through a frequency converter device, is implemented by a local oscillator (hereinafter "LO") leak cancellation circuit. A feedback correction loop, for a radio frequency (RF) transmitter or receiver, reduces an undesired local oscillator leak generated through a single input frequency converter device (20), such as a mixer, by a unique detection circuit (30). A unique nulling circuit (40) is also implemented for a multiple input frequency converter device, such as a quadrature modulator.

    3.
    发明专利
    未知

    公开(公告)号：BR9902667A

    公开(公告)日：2000-03-14

    申请号：BR9902667

    申请日：1999-07-09

    Applicant: LUCENT TECHNOLOGIES INC

    Inventor： KANNELL GEORGE KENNETH ,  MYER ROBERT EVAN ,  SREENATH KRISHNAMURTHY

    IPC: H03C3/00 ,  H03C1/06 ,  H03D7/00 ,  H04B1/04 ,  H04B1/26

    Abstract: A method for reducing the level of an undesired signal, generated through a frequency converter device, is implemented by a local oscillator (hereinafter "LO") leak cancellation circuit. A feedback correction loop, for a radio frequency (RF) transmitter or receiver, reduces an undesired local oscillator leak generated through a single input frequency converter device (20), such as a mixer, by a unique detection circuit (30). A unique nulling circuit (40) is also implemented for a multiple input frequency converter device, such as a quadrature modulator.

    5.
    发明专利
    未知

    公开(公告)号：DE69923632D1

    公开(公告)日：2005-03-17

    申请号：DE69923632

    申请日：1999-07-06

    Applicant: LUCENT TECHNOLOGIES INC

    Inventor： KANNELL GEORGE KENNETH ,  MYER ROBERT EVAN ,  SREENATH KRISHNAMURTHY

    IPC: H03C3/00 ,  H03C1/06 ,  H03D7/00 ,  H04B1/04 ,  H04B1/26

    Abstract: A method for reducing the level of an undesired signal, generated through a frequency converter device, is implemented by a local oscillator (hereinafter "LO") leak cancellation circuit. A feedback correction loop, for a radio frequency (RF) transmitter or receiver, reduces an undesired local oscillator leak generated through a single input frequency converter device (20), such as a mixer, by a unique detection circuit (30). A unique nulling circuit (40) is also implemented for a multiple input frequency converter device, such as a quadrature modulator.

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