Surveillance device detection utilizing non linear junction detection and reflectometry
First Claim
1. An apparatus for detecting the presence of a corrosive junction or an electronic device coupled to a line under test, said apparatus comprising:
- a signal generator for generating a reflectometry test signal and a non-linear junction detection test signal and coupling said test signals to said line under test;
an analog-to-digital converter for receiving response signals from said line under test and converting said response signals into digital data; and
digital processing circuitry for selectively controlling said signal generator to generate said reflectometry test signal and said non-linear junction detection test signal and processing said digital data received in response to said generated signals to locate impedance anomalies on said line under test and examining a re-radiated signal at a harmonic frequency of said transmitted non-linear junction detection signal to determine if any semiconductor based non-linear junctions are coupled to said line under test; and
an output for communicating results to an operator of said apparatus.
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Accused Products
Abstract
An apparatus for detecting concealed surveillance devices coupled to a transmission line uses either a time domain or frequency domain reflectometry operation to locate any impedance anomalies on the transmission line and a non-linear junction detection operation to classify the located impedance anomalies as semiconductor or non-semiconductor based anomalies. The reflectometry operation utilizes the reflection of a test signal to determine the distance to any reflecting impedance anomalies on the transmission line that may be indicative of an electronic device being coupled to the transmission line. The non-linear junction detection operation then compares the amplitudes of re-radiated second and third harmonics of a transmitted fundamental frequency signal to determine if the reflecting impedance anomalies are the result of a semiconductor based non-linear junction. A DC bias voltage and a balanced load may be added to the transmission line to enhance the line'"'"'s response to the test signals. Any unidentified semiconductor based anomalies are manually inspected to determine if they represent convert surveillance devices.
39 Citations
19 Claims
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1. An apparatus for detecting the presence of a corrosive junction or an electronic device coupled to a line under test, said apparatus comprising:
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a signal generator for generating a reflectometry test signal and a non-linear junction detection test signal and coupling said test signals to said line under test; an analog-to-digital converter for receiving response signals from said line under test and converting said response signals into digital data; and digital processing circuitry for selectively controlling said signal generator to generate said reflectometry test signal and said non-linear junction detection test signal and processing said digital data received in response to said generated signals to locate impedance anomalies on said line under test and examining a re-radiated signal at a harmonic frequency of said transmitted non-linear junction detection signal to determine if any semiconductor based non-linear junctions are coupled to said line under test; and an output for communicating results to an operator of said apparatus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A device for determining whether an electronic device is coupled to a line under test and locating any such electronic device identified, said device comprising:
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a signal generator for selectively generating signals and coupling said signals to said line under test; an analog-to-digital converter for converting response signals received from said line under test into digital data; and a digital processor for selectively controlling said analog-to-digital converter and said signal generator wherein said processor further comprises; reflectometry processing logic for implementing a reflectometry operation to locate any impedance anomalies on said line under test; and non-linear junction detection processing logic for performing a non-linear junction detection operation to determine if any semi-conductor based non-linear junctions are coupled to said line under test. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification