초록 ▼

A non-linear junction detector designed for counter surveillance measures achieves superior performance by using a single circularly polarized antenna to transmit a signal and to receive harmonics of the transmitted signal that are re-radiated by a non-linear junction such as would be found in a eav

A non-linear junction detector designed for counter surveillance measures achieves superior performance by using a single circularly polarized antenna to transmit a signal and to receive harmonics of the transmitted signal that are re-radiated by a non-linear junction such as would be found in a eavesdropping device containing a semiconductor. The antenna is mounted on a telescoping antenna extension assembly. A single electrically conductive cable is contained inside the antenna and connects the antenna to the transceiver case which houses the non-linear junction detector electronics. A cable winder is built into the antenna and is employed to provide automatic dispensing and retraction of the cable when the antenna extension assembly is extended or retracted. A display is built into the antenna head assembly to provide signal strength indications and operational information concerning the functioning of the non-linear junction detector to the user of the device. The control signals and power for the display are multiplexed onto the single electrically conductive cable.

대표청구항 ▼

[ What is claimed is:] [23.] An apparatus for detecting the presence of covert surveillance devices containing non-linear semi-conductor junctions, the apparatus comprising:a transmitter for producing a transmit signal having an amplitude;a single broadband antenna for transmitting the transmit sign

[ What is claimed is:] [23.] An apparatus for detecting the presence of covert surveillance devices containing non-linear semi-conductor junctions, the apparatus comprising:a transmitter for producing a transmit signal having an amplitude;a single broadband antenna for transmitting the transmit signal and for receiving a second harmonic signal and a third harmonic signal of the transmitted signal that have been re-radiated by a non-linear junction;a receiver for receiving the second and third harmonic signals from the broadband antenna, producing signals corresponding to the amplitude of the second and third harmonics and producing demodulated versions of the second and third harmonic signals;a display located on the antenna for displaying an alpha-numeric message, a transmit power reading, a second harmonic signal power reading, and a third harmonic signal power reading;an electrically conductive cable for electrically connecting the transmitter and the receiver to the broadband antenna and for providing power and control signals to the display;a diplexer for separating the transmit signal from the receiver, the diplexer comprising a low pass filter for preventing any harmonics generated by the transmitter from interfering with the received harmonic signals and a high pass filter for preventing the transmitted signal from entering the receiver;a retractable antenna extension assembly for supporting the broadband antenna and housing the single electrically conductive cable that electrically connects the receiver and the transmitter to the broadband antenna;an antenna connection joint attached to the retractable antenna extension assembly and the broadband antenna in a manner that provides two axis of rotation for the broadband antenna;a keypad for providing user control of the non-linear junction detector;a microprocessor control circuit for receiving signals from the keypad, sending signals to the display, receiving signals corresponding to the amplitudes of the second and third harmonic signals from the receiver, receiving demodulated versions of the second and third harmonic signals from the receiver, producing encoded audio signals representing demodulated versions of the second and third harmonic signals and producing encoded audio signals representing the amplitude of the second and third harmonic signals;a cable winder for automatically removing any slack produced in the electrically conductive cable when the retractable antenna extension assembly is retracted and providing additional electrically conductive cable when the retractable antenna extension assembly is extended;a transceiver case for mounting the retractable antenna extension assembly and containing the transmitter, receiver and microprocessor control circuit;a connection joint for rotatably connecting the transceiver case to the retractable antenna extension assembly;a slip ring assembly for electrically connecting the conductive cable to the display;an audio circuit for receiving encoded audio signals representing demodulated versions of the second and third harmonic signals and producing sounds corresponding to the demodulated versions of the second and third harmonic signals; andan infrared transmitter for receiving the encoded audio signals representing the amplitude of the second and third harmonics from the microprocessor control circuit and transmitting the signals to a pair of wireless infrared headphones.