| 摘要 |
PURPOSE:To widen the effective frequency band by changing a bias voltage of a varactor diode in a feedback circuit so as to vary the range of a frequency division frequency. CONSTITUTION:Amplifiers 3,4 of a closed loop are coupled by a series connection circuit comprising DC blocking capacitors 8, 9, a parallel connection circuit comprising a varactor diode 6 and a choke inductor 10 is connected to the connecting point of the capacitors 8, 9, a bias terminal 7 is provided via a choke inductance 10 to constitute the feedback circuit. In changing the bias voltage of the diode 6, the loop delay circuit is changed. In this case, when the bias voltage is larger, since the loop delay time is small, the frequency division band depends on a high frequency band, but when the bias voltage is small, the loop delay time is larger and the frequency division band is moved to a low frequency band. As a result, the effective frequency band is widened.
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