| 摘要 |
PURPOSE:To prevent the generation of unneeded waves and the sudden variaftion in output level, by controlling the bias current of an IMPATT diode corresponding to the magnitude of an input signal. CONSTITUTION:When input signal level Vin decreases, the output of inversional amplifier 7 appears and control transistor Tr8 starts operating. As a result, since the collector potential of Tr8 decreases by the current composed of the collector current of Tr8 flowing to resistor 14 and the base current of Tr9, the base voltage of Tr9 decreases to cause a current flowing to the IMPATT diode to decrease and, in consequence, the self-excitation oscillation output of IMPATT oscillator 1 also decreases. Therefore, when Vin becomes below a certain value, the bias current of oscillator 1 decreases and the ascillation output is decreased. Charaeteristics of Vin of oscillator 1 to the bias current and output level are shown in reference to control unneeded part (alpha) of the bias current with small Vin, part (beta) where the bias current is controlled corresponding to Vin, and saturation part (gamma). |
