| 摘要 |
PURPOSE:To prevent the deterioration of the transmission characteristics of signals by changing the reverse voltages of variable capacity diodes to control delay time and to vary matching resistance and compensating the fluctuations in the characteristics in each of sections of a delay line by a compensation circuit. CONSTITUTION:The delay line 12 is constituted of inductors L and the variable capacity diodes VC and the electrostatic capacity of the diodes VC is controlled by changing the control voltage V, and varying the magnitude of the reverse voltages, by which the delay time is changed. A variable resistance circuit 13 is then provided as the matching resistance of the delay line 12 in accordance with the change in the characteristic impedance arising from the change in the delay time and the gain of variable gain amplifier 14 is changed by the control voltage V2, by which the input resistance of the circuit 13 is continuously changed. The compensation circuit 17 is provided and the voltage dividing ratios of voltage dividers K1, K2,... Kn are adjusted in each of the sections to trim and compensate the fluctuations in the capacity of the respective diodes VC, by which the characteristic impedances of the respective sections are made uniform. The continuous control of the delay time is thus executed without deteriorating the transmission characteristics of the signals. |
