| 摘要 |
<p>Judgment means (104,106,108) provides a first output alternating signal to a DIVIDED 2 frequency-divider (111) and also a frequency-division control signal at a first level to operate the DIVIDED 2 frequency-divider, when a first input alternating signal is applied to an input terminal. The first output alternating signal frequency divided by the DIVIDED 2 frequency divider is applied to an NOR gate (116), to which a first gate control signal is applied from the judgment means so as to allow the frequency divided first output alternating signal to pass the NOR gate. When a second input alternating signal is applied to the input terminal, the judgment means provides the frequency-division control signal at a second level to the DIVIDED 2 frequency-divider which, in turn, provides a second gate control signal to the NOR gate. At this time, the judgment means also provides a second output alternating signal to the NOR gate. The NOR gate with the second gate control signal applied thereto passes the second output alternating signal therethrough. The first and second input alternating signals alternate about different reference levels. <IMAGE></p> |
