| 摘要 |
PURPOSE:To make narrow the AFC holding range without lowering the detection sensitivity of amplitude of an AFC output, by inserting a resistance between the output point of the constant-current type differential amplifying circuit, and the intersection point of the load resistances. CONSTITUTION:A reference signal is provided to the base of the transistors 13-16, a phase shift signal is provided to the emitter of the transistors 13-16, and the phase shift detection by multiplication is executed between the base and emitter of these transistors 13-16. The phase detection output operates the constant-current differential amplifier of the transistors 23-25 by means of the current Miller circuit by the transistors 17-22. The resistance 37 for making narrow the holding range of the AFC is inserted between the output point (f) of said constant-current differential amplifier and the intersection point of the load resistances 29, 30. |
