| 摘要 |
A non-linear junction detector (NLJD) for detecting and locating concealed electronic devices or devices which contain metal contacts or metal junctions has a multi-frequency transmitter configured to illuminate a sweep area with a plurality of RF illumination signals at different frequencies and a receiver configured to receive a return signal from target objects within the sweep area. The return signals are provided to a processor configured to: determine amounts of energy in the return signal within predetermined frequency bands; and compare the amounts of energy in the predetermined frequency bands with a database of signatures each indicative of a specific target object or class of target objects; and provide an indication of likely target object or class of target objects corresponding to the return signal. The RF illumination signals may be predetermined set of frequencies (e.g. GSM, 3G, 4G, WiFi, Bluetooth, NFC) selected according to a target type and corresponding to known frequencies of weakness in the RF screening of the target type. |
