| 摘要 |
PURPOSE: To start the oscillation from a known state in response to a level of an input logic clamp signal by providing a clamping resistor, a transistor(TR) connecting to one terminal of for an AC voltage of the clamping resistor, a means selecting one terminal of tank coils d, c and applying a bias to it and a clamp switch. CONSTITUTION: In the clamp operation of a tank circuit, the oscillation is stopped for 6 periods causing an input logic on a clamp line 28 and the circuit is started when not clamped and makes free running from a known state. When a logic clamp signal on the line 28 is low, a transistor(TR) 18 is nonconductive by a bias, and a TR 22 is conductive by a bias. Thus, TRs 36, 38 in diode connection are nonconductive because a saturation voltage of the collector and the emitter of the TR 22 is low and a TR 44 remains turned off. Thus, a high impedance coil 10 is connected in parallel to the tank circuit and a capacitor 14 is connected in series to a capacitor 12. Thus, the tank circuit is freely oscillated. |
