| 摘要 |
An apparatus for remotely controlling an auxiliary doorbell chime includes a sensing unit mounted near a doorbell chime and a remote unit mounted at a location where chime normally cannot be heart. The sensing unit has an acoustic transducer responsive to a source acoustic frequency wave generated by the doorbell chime for generating a transducer signal, a signal processing circuit responsive to the transducer signal for generating a transmitter activation signal, a radio frequency transmitter responsive to the transmitter activation signal for generating a ratio frequency output signal and a first antenna responsive to the radio frequency output signal for transmitting a radio frequency wave. The remote unit has a second antenna responsive to the radio frequency wave for generating a radio frequency input signal, a radio frequency receiver responsive to the radio frequency input signal for generating a generator activation signal and an acoustic generator responsive to the generator activation signal for generating an auxiliary acoustic frequency wave representing a presence of the source acoustic frequency wave at the acoustic transducer. If the doorbell generates more than one source acoustic frequency wave, the sensing unit can be responsive to other source acoustic frequency waver for generating another radio frequency wave and the remote unit can be responsive to the another radio frequency wave for generating another auxiliary acoustic frequency wave representing a presence of the another source acoustic frequency wave at the sensing unit.
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