| 摘要 |
PROBLEM TO BE SOLVED: To automatically select and change-over an operation mode for announcing an incoming call by providing a means by which a low frequency vibration intrinsic to a human body is correctly detected by means of a sensor and announcing the incoming call by means of the vibration when an equipment is carried and by means of sound or light unless it is carried. SOLUTION: A signal outputted from the sensor 1 is amplified to a prescribed level in an amplifier circuit 2 and supplied to a detection circuit 3 as a sensor output signal. The detection circuit 3 detects the sensor output signal and outputs a wave detection output signal with a prescribed level during a period when the vibration intrinsic to the human body is being outputted. The wave detection output signal is supplied to a comparator 4 and compared with a prescribed reference signal. A comparison output signal becomes a high level signal during the period when the low frequency vibration intrinsic to the human body is detected and becomes the low level signal in the period except it. The comparison output signal is transmitted to a control circuit 5 constituted of CPU, etc., and the operation mode for announcing the incoming call is selected and changed-over in accordance with the present state of a portable telephone set and the level of the comparison output signal. |
