Signal tracking electronically tunable filter
    1.
    发明授权
    Signal tracking electronically tunable filter 失效
    信号跟踪电子可调谐滤波器

    公开(公告)号:US5019792A

    公开(公告)日:1991-05-28

    申请号:US425144

    申请日:1989-10-23

    IPC分类号: H01P1/218 H03J7/02

    CPC分类号: H01P1/218 H03J7/02

    摘要: A tunable bandpass filter for radio frequency energy with a phase-locked loop for tracking an input signal and to control the filter to keep the center frequency of the passband coincident with the frequency of the input signal is shown. Using a Yttrium Iron Garnet (YIG) filter as a frequency determining element and as a passive dispersive reference element for a frequency discriminator, the bandpass filter uses the output signal of the discriminator to form a fine tuning signal to control the center frequency of the passband of the YIG filter.

    摘要翻译: 示出了用于射频能量的可调谐带通滤波器,其具有用于跟踪输入信号的锁相环并且控制滤波器以保持通带的中心频率与输入信号的频率一致。 使用钇铁石榴石(YIG)滤波器作为频率确定元件,并作为用于鉴频器的无源色散参考元件,带通滤波器使用鉴频器的输出信号形成微调信号,以控制通带的中心频率 的YIG滤波器。

    Low noise magnetically tuned resonant circuit
    2.
    发明授权
    Low noise magnetically tuned resonant circuit 失效
    低噪声磁调谐谐振电路

    公开(公告)号:US4758800A

    公开(公告)日:1988-07-19

    申请号:US33306

    申请日:1987-04-02

    CPC分类号: H01P1/218

    摘要: A magnetically tuned resonant circuit having improved noise performance includes a ferrimagnetic or gyromagnetic body such as a YIG sphere which is disposed within r.f. structure, The r.f. structure is disposed between a pair of pole pieces of a biasing magnet and flux return path. Several techniques are described for reducing fluctuations in magnetic fields through the gyromagnetic body. The gyromagnetic body is isolated from conductive surfaces, or the bulk of conductive surfaces in the region adjacent to the magnetic body are reduced. Further, a technique is also described which provides a break in the electrical continuity around the r.f. structure. Each of these technique reduce the magnitude of thermally induced eddy current flow in conductive regions adjacent to the resonant body. It is believed that such eddy current flow produce random magnetic field variations which produce random variations in the frequency characteristics of conventional magnetically tuned resonant circuits.