| 摘要 |
PURPOSE:To foresee the oscillation stop of an oscillation circuit accurately by detecting that the amplitude of an oscillation output signal lowers to below a certain value. CONSTITUTION:An inverter 9 is an amplifier directly coupled to an oscillator circuit and an inverter 10 is an amplifier differing in logic level from the inverter 9. When the oscillation amplitude is large, the output of the inverter 9 is transmitted to a frequency dividing circuit via an inverter 11, and the pulses of the same frequency as that of the oscillation signal is outputted to the output of an inverter 12. On the other hand, if the oscillation amplitude is slight, the oscillation signal is amplified by the inverter 9 and the inverter 11 is driven but the output, of the inverter 10 does not cross the logic level of the inverter 12 and therefore the output of the inverter 12 is always the H level. Hence, the oscillation stop is foreseen by monitoring the ouput level of the inverter 12. |
