A portable electronic device includes a transmitting circuit, an X-ray detector, and a controller. The transmitting circuit includes a power amplifier for amplifying radio waves. The detector is arranged to detect X-rays radiated from an installation arranged on a passageway to an area where radiation of electromagnetic waves is restricted. When X-rays with a certain intensity or more are detected by the detector, a controller recognizes that the device is about to enter the area, and reduce the gain of the power amplifier, so that the transmitting circuit is set to be unable to radiate radio waves.

A selective blocker for targeted mobile terminals. A signal monitor determines when a targeted mobile terminal is transmitting a signal to a base station. A signal analyzer identifies characteristics of the terminal signal and a processor produces a blocking response based on one or more characteristics. The blocking response is transmitted to the targeted mobile terminal to block communications between the targeted mobile terminal and the base station using the minimum power needed to effectively block the terminal signal so as to limit interference with non-targeted mobile terminals.

The test results found that the EMI impact depended on the UWB power that fell within the receiver passband. Specifically, EMI occurred when the average power in the receiver passband was approximately equal to the desired signal level of the receiver. One waveform, TW7, did not cause EMI because the average power was too low. Three waveforms, TW1, TW2, and TW6 only caused EMI when the receiver was tuned to the frequency of the UWB spectral component. Three waveforms, TW3, TW4, and TW5, caused EMI at all receiver frequencies. As noted, these tests were performed to determine the susceptibility of various RF receiver (radars and communications systems) devices to UWB signals. The tests were not intended to evaluate the use of UWB signals for jamming purposes.

An ultra wideband (UWB) jamming system comprises a processor, a memory, a pulse generator, one or more UWB transmitters, and one or more UWB antennas. In an exemplary embodiment of the present invention, the RF signals of a threat transmission or an RF-triggered explosive device (RTED) are evaluated and a set of interference parameters defined for the RF signal of that device. The interference parameters are predetermined to interfere with the reception or transmission of the RF signal. The interference parameters are sent to a pulse generator that drives one or more UWB transmitters to generate a signal has a statistically high probability of jamming or introducing an error in the threatening transmission.

The present invention provides a method for a central control computer, located within a given environment, to wirelessly communicate with, control and enhance the use of various mobile electronic devices entering the given environment. These devices each possess a wireless transceiver. The central control computer transmits a discovery signal and control message to these mobile electronic devices within the range of the wireless transmissions. This allows discovery of the central control computer by the mobile electronic device and, after setting up a communication, the mobile electronic device disables one or more of its features as instructed by the central control computer. Furthermore, enhancements are provided by making available substitute features for the features of the mobile electronic device that were limited or disabled and by making available features not contained within the mobile electronic device itself.