| 摘要 |
PROBLEM TO BE SOLVED: To form a dead zone for a receiver in a certain area by a simple device, and to prevent the influence of a portable telephone set on medical equipment or the like. SOLUTION: Only components in a frequency band for interference are extracted by a filter 2 from a wide band noise such as a white noise outputted by a wide band noise generator 1, and radiated from an antenna 3. This interference radio wave has a weak level to be received by a receiver so that the device itself can be made compact and inexpensive, and a generated noise can be prevented from affecting medical equipment or the like. |
