초록 ▼

A non-linear junction detector designed for counter surveillance measures achieves superior performance by transmitting a series of pulses and receiving harmonics of the transmitted pulse signals that are re-radiated by a non-linear junction such as would be found in an eavesdropping device containi

A non-linear junction detector designed for counter surveillance measures achieves superior performance by transmitting a series of pulses and receiving harmonics of the transmitted pulse signals that are re-radiated by a non-linear junction such as would be found in an eavesdropping device containing a semiconductor. The transmit power of the series of pulses is varied and the amplitudes of the harmonics received at the different power levels are compared to determine the type of non-linear junction detected. The received harmonic signals are demodulated to create signals having a frequency in the audible range of human ears. The demodulated signals are broadcast so that an operator of the non-linear junction detector can audibly distinguish between the noise responses produced by the different types of non-linear junctions. The harmonic signals are analyzed to determine if the harmonic, signals correspond to signals produced by a known type of non-linear junction device such as a video camera or tape recorder. Data generated by the non-linear junction detector is displayed to an operator of the detector and may be stored for later analysis.

대표청구항 ▼

[ What is claimed is:] [1.] A method of detecting the presence of a non-linear junction, the steps of the method comprising:transmitting a transmit signal at a transmit power level and a transmit frequency;receiving and sampling a second harmonic signal and a third harmonic signal that were re-radia

[ What is claimed is:] [1.] A method of detecting the presence of a non-linear junction, the steps of the method comprising:transmitting a transmit signal at a transmit power level and a transmit frequency;receiving and sampling a second harmonic signal and a third harmonic signal that were re-radiated by a non-linear junction at harmonic frequencies of the transmitted signal with an analog-to-digital converter to produce sampled values;examining the sampled values to determine if a non-linear junction is present; andcomparing the sampled values of the second and third harmonic signals to determine if a detected non-linear junction is formed by two dissimilar metals or a semiconductor.