| 摘要 |
PROBLEM TO BE SOLVED: To inhibit a speech by a portable telephone set that has problems of noisy sound and disturbing electromagnetic waves from the portable telephone set within a prescribed area by allowing a speech inhibit device to send an electric signal with a frequency the same as a transmission radio wave frequency between the portable telephone set and a base station so as to cause crosstalk and cross modulation faults in a reception section of the portable telephone set thereby allowing the portable telephone set to be unable to receive a transmission radio wave from the base station. SOLUTION: When a portable telephone set radio wave detection circuit 16 detects a radio wave from a portable telephone set to a base station, a control circuit 18 activates a signal generator 22 to generate an electric signal with a frequency the same as a radio wave frequency from the base station in response to a radio wave sent from the portable telephone set to the base station and to provide an output. As a result, a radio wave with a frequency the same as the frequency of the radio wave from the base station to the portable telephone set is sent from an antenna 14 and reaches the portable telephone set. Thus, the portable telephone set cannot receive the reply radio wave sent from the base station by this effect resulting that a speech channel between the portable telephone set and the base station cannot be set and then a speech between them is inhibited. |
