| 20120094625 | DETECTING UNAUTHORISED RADIO COMMUNICATIONS DEVICES - A method for detecting unauthorised radio communications devices, the method including the steps of filtering received radio frequency signals into desired signals having a frequency band characteristic of an unauthorised radio communications device and undesired signals having a different frequency band characteristic of an authorised radio communications device, comparing respective levels of the desired and undesired signals with respective predetermined threshold levels, and generating detection signals indicative of the presence of the unauthorised radio communications device only if the desired signals exceed their predetermined threshold level and the undesired signals do not exceed their predetermined threshold level, thereby passively discriminating between the authorised and unauthorised radio communications devices, and interference therebetween. | 04-19-2012 |
