Abstract: A method of filtering an input signal which includes noise cyclically repeating at a known noise frequency, to substantially remove said noise from the input signal is provided. The method includes sampling the input signal at a frequency corresponding to a whole multiple “N” of the noise frequency; sequentially storing the samples in 0-N storage devices; sequentially subtracting the sample in each storage device from the sample previously stored in the Nth storage device preceding the respective storage device, to thereby produce for each sample, a difference sample in which the cyclically repeating noise is effectively cancelled from the respective sample; and sequentially outputting the difference samples to produce an output signal from which the cyclically repeating noise has been substantially removed.

Abstract: An intrusion detection system and method are provided that can utilize impulse radio technology to detect when an intruder has entered a protection zone. In addition, the intrusion detection system and method can utilize impulse radio technology to determine a location of the intruder within the protection zone and also track the movement of the intruder within the protection zone. Moreover, the intrusion detection system and method can utilize impulse radio technology to create a specially shaped protection zone before trying to detect when and where the intruder has penetrated and moved within the protection zone.

Abstract: The present invention provides a security system that can provide a user with data on the directional movement, velocity and location of an object within and around the perimeter of a structure with the use of radio energy. The system comprises a sensor unit having at least one antenna for transmission of a signal into a defined area of the structure. Any intrusion in the area is detected upon a change in the waveform received by the antenna. A received signal is transmitted from the sensor unit to a control unit, comprising, in part, a preprogrammed data processing unit that can determine the movement of the intruder. Utilization of a plurality of sensor units allows the user to obtain additional information on the velocity and location of the intruder. Additionally, as with conventional security systems, the system can provide an electrical signal to activate a sound and/or light device to attract the attention of the intruder and warn others of the intruder's presence.

Abstract: A demodulator of an evaluating unit for a device for detecting objects derives a useful signal from a supplied input signal with the aid of a carrier signal. The demodulator further derives a test signal with the aid of a modulated carrier signal. An evaluator detects as a function of the useful signal whether an object is being detected and, as a function of the test signal the functionality of the device.

Abstract: In a detection system for detecting intruders in the vicinity of a predetermined path or line defined by a distributed antenna, for example an open transmission line, an array of discrete antennas are provided alongside the distributed antenna and within a predetermined distance therefrom. The antennas are spaced apart from each other and the distributed antenna and define a plurality of detection zones. A radio frequency transmitter is connected to one of the distributed antenna and the array of discrete antennas, and a complementary receiver is connected to the other of the distributed antenna and the array of discrete antennas. A control unit controls the transmitter, receiver and array of antennas to exchange radio frequency energy several times via the distributed antenna and selected ones of the array of antennas and to detect perturbations caused by an intruder moving adjacent the path and adjacent a particular antenna.

Abstract: An outdoor microwave transceiver intrusion detector that alternately transmits pulses of RF energy at two different frequencies and uses range and direction of travel information derived from the phase of the two Doppler responses to optimize the signal processing and apply range dependent thresholds. The time delay between the onset of the transmitted pulse and the sample of the Doppler response is controlled to provide an accurate range cutoff. The two frequencies are selected so that the difference in phase of the Doppler response at the two frequencies increases from zero to ninety degrees as the target goes from the Transceiver to the maximum range. Digital signal processing is used to measure the difference in phase of the two Doppler responses and translate this information into location of the target. The location information is used to create a number of range bins.

Abstract: A motion detector based on the Doppler principle contains a microwave module for emitting a microwave signal containing at least two frequencies into a room under surveillance and for receiving the radiation reflected from the latter. An evaluation stage is connected to the microwave module and generates first and second Doppler signals from the received radiation. The first and second Doppler signals have a phase difference which is proportional to the distance of an object reflecting the microwave signal. The phase difference is determined by an integral transformation. In addition, the relative size of an object and the direction of travel of an object reflecting the microwave signal can be determined by the evaluation stage.

Abstract: There is disclosed an apparatus and method for reducing power consumption in physiological condition monitors that use a memory data storage device that operates in a high power mode when data is being written to the memory data storage device and operates in a low power mode when inactive. The apparatus comprises: 1) a controller for receiving incoming data to be written to the memory data storage device; and 2) a first low power buffer coupled to the controller. The controller stores the incoming data in the first low power buffer until a predetermined amount of incoming data has been accumulated in the first low power buffer and transfers the accumulated predetermined amount of incoming data to the memory data storage device in a single data transfer.

Abstract: The invention relates to a motion detector or proximity switch for detecting moving objects, wherein a high frequency electromagnetic radiation is generated by a free running oscillator and transmitted via a transmitter antenna. The transmitter antenna detects the Doppler modified radiation reflected by the moving object as a function of its phase position or amplitude variation. The radiation is compared with the transmitted radiation parameters in an evaluation device with a view to producing an output signal. The inventive detector is characterized in that it included a free running oscillator having a feedback guaranteed by at least one transmitter antenna ANT RX and at least one receiver antenna ANT TX which are oriented towards the object and coupled via a side or leakage radiation.

Abstract: A system for detecting and tracking movement within a building has a plurality of portable microwave detector units for deploying outside the walls of the building. Each detector unit has a microwave module for transmitting microwaves through the building walls into a monitored area and for detecting radiation reflected back to the unit from the monitored area, and an output device for transmitting an alarm signal from the unit if a shift is detected in the reflected radiation frequency, indicating movement within the area. A receiver unit receives alarm signals from the detector units and produces an output signal for each detector unit currently detecting movement to provide the user with information on the location of any movement within the building.

Abstract: An electromagnetic intrusion detection system which has a transmitter that produces a radio frequency output which is received by an antenna which receives the output and radiates an electromagnetic field into the surrounding space. This in turn responds to the presence of an object or an environmental condition causing absorption and/or reflection. A monitoring apparatus monitors power consumption and thus provides a signal output relating to the environmental condition and/or intrusion.

Abstract: A motion detector combines an FCC approved homodyne pulsed range-gated radar (“RGR”) detector (10) and a PIR detector (158). Narrow microwave pulses are transmitted at a predetermined pulse repetition frequency (“PRF”) and the pulses are reflected by a target. The RGR detector senses the presence of moving human sized objects within predetermined ranges. Moving objects beyond the ranges are not sensed. The RGR detector employs a pulsed microwave oscillator (12) that is triggered by a system clock (14) and immediately retriggered after a 3 to 100 nanosecond delay (20). The duration of each pulse is 3 to 20 nanoseconds with a half-sine envelope shape. The RGR employs a homodyne detector (36) and shares an antenna (38) with the transmitter. The receiver range is determined by the delay imposed between the transmitted pulses, the first being a transmitted pulse and the second being a local oscillator pulse. Each received 5.8 GHz pulse is mixed down to a baseband by the homodyne detector.

Abstract: An Ultra Wideband (UWB) short-range radar system is used for the detection of targets in clutter. Examples of targets on the ground include human walkers, crawlers and runners, and vehicles. The UWB sensor can also be used to detect small approaching boats in different levels of sea clutter or airborne targets like hang gliders. One of the primary differences between this device and other UWB radar sensors is the manner in which the bias on the threshold detector is set as well as the logic circuitry used to find targets in clutter while maintaining a low false alarm rate. The processing is designed to detect targets in varying degrees of clutter automatically. There may be no front panel controls other than an ON-OFF switch. The system is lightweight, low-cost, and can be easily installed in minutes.

Abstract: In an entering detecting system for vehicles, a received ultrasonic signal is amplified by an amplifier circuit so that a Doppler signal may be generated from an amplified signal and a transmission signal for detecting an entering of unauthorized person into a vehicle compartment. An operational amplifier circuit of the amplifier circuit has an output limiter circuit. The output limiter circuit has diode series circuits which are connected to a feedback resistor of an operational amplifier.

Abstract: A method for determining if a motion detector is in a masked condition at the time power is applied to the detector. When power is first applied to the motion detector it enters a mask detection state which runs concurrently with activity and alarm detection routines. Any infrared motion that is detected after the detector has warmed up and stabilized will terminate the mask detection state. If a predetermined amount of microwave Doppler sensor activity is detected within the field of view without detection of infrared activity, a mask condition is declared.

Abstract: A dual-sensing intrusion detection device for detecting an intruder comprising a PIR sensor and a microwave sensor. The device comprises PIR processing means and microwave processing means, means for summing the processed PIR signal with the processed microwave signal to generate a summed signal, and means for comparing the summed signal to a sum threshold value to determine if an alarm condition exists. The sum threshold value is selected for optimal discrimination between a human intruder and an animal presence. An additional feature of the intrusion detection device is the generation of a PIR difference signal. This feature allows the device to compensate for the limited bandwidth of the PIR sensor and to be more sensitive to a human intruder. The processing of the sensor signals includes an integration technique that sums the amplitude values of the signal and causes the sum to decay at a slow rate.

Abstract: There is disclosed an apparatus and method for reducing power consumption in physiological condition monitors that use a memory data storage device that operates in a high power mode when data is being written to the memory data storage device and operates in a low power mode when inactive. The apparatus comprises: 1) a controller for receiving incoming data to be written to the memory data storage device; and 2) a first low power buffer coupled to the controller. The controller stores the incoming data in the first low power buffer until a predetermined amount of incoming data has been accumulated in the first low power buffer and transfers the accumulated predetermined amount of incoming data to the memory data storage device in a single data transfer.

Abstract: An electronic device including a wave transmitter covering a determined spatial sensing field, and a wave receiver for controlling an automatic device; a radiating antenna including a waveguide having lateral faces and slots arranged on one of the lateral faces, wherein the slots radiate in planes substantially perpendicular to a longitudinal direction of the waveguide, and wherein the wave transmitter and the wave receiver are arranged at one end of the waveguide; a matched load arranged at an opposite end of the wave guide; substantially identical reflectors arranged over substantially the whole length of the waveguide, wherein the reflectors extend essentially symmetrically with respect to longitudinal plane of symmetry of the waveguide and making a predetermined angle with one another, and wherein the waveguide and the reflectors are composed of at least one piece.

Abstract: An electronic intrusion detection system for monitoring environments having at least one electronic sensor responsive to movements occurring in the environment and adapted to modify at least one characteristic of its electrical output in response to the presence of a moving body in the environment. An alarm is signaled when the modification meets a predetermined condition. A transducer is provided for continuously converting the modification of the output from the electric sensor into a signal that can be perceived by a human being. An alarm control unit connected to the alarm and transducer forwards the signals to the surveillance personnel through a telephone line.

Abstract: An automatic lamp control device in which a Doppler radar module, a switching unit for switching a lamp circuit on and off, a circuit configuration for evaluating Doppler radar module signals and for producing signals for controlling the switching unit, and a power supply unit for supplying current to the Doppler radar module and to the circuit configuration are provided on a printed circuit board configuration. The lamp control device reacts to movements within the transmitting and receiving range of the Doppler radar module. The range is independent of the ambient temperature. The lamp control device can be configured to save space, in such a way that it can be integrated completely in a standard flush-mounted box.

Abstract: In accordance with the method, the received signal is quadrature demodulated by mixing it with two signals with a relative phase difference of .pi./2 and having the same frequency as the emitted carrier, the absolute value of each of the demodulated signals of each pair of signals obtained is compared to a respective threshold to determine valid pairs if the absolute value of at least one of the two demodulated signals is higher than the threshold and invalid pairs otherwise and the number of successive rotations of the vector whose coordinates correspond to the values of the signals of the successive valid pairs is counted. For each invalid pair the value of the count is progressively reduced. The alarm is tripped if the value of the count reaches a given threshold.

Abstract: A multiple sensing technology-based occupancy sensor. Ultrasonic and infrared sensors are used to produce first and second occupancy estimator signals that are combined using a fusion based detection algorithm to produce a combined estimator signal. The combined estimator is then used to switch electrical loads when the combined estimator signal is above a predetermined threshold. The result is an occupancy sensor that has a very high probability of occupancy detection and a low probability of false tripping.

Abstract: A motion detection unit for detecting motion by means of Doppler frequency shift which comprises: a microwave circuit board comprising an oscillator, a hybrid coupler circuit element and a mixer; an antenna board comprising at least one transmit and receive antenna; and a ground plane layer, the two boards being superimposed with the ground plane layer intervening, wherein, in operation, the hybrid coupler circuit element divides power from the oscillator into power for the antenna transmission signal and local oscillator (LO) power to the mixer, and directs a received signal from the antenna to the mixer, the local oscillator (LO) power and the received signal being combined in the mixer to produce a Doppler signal output.

Abstract: A combined type intrusion and attack sensing device was a microwave oscillation and Doppler detect circuit an intrusion band-pass filter, an attack band-pass filter, two comparators, two alarm driving circuits, and a suspended object. The combined type intrusion and attack sensing device adopts the Doppler effect to sense an intrusion and employs a microwave antenna to transmit a signal in the microwave band within a predetermined range. The signal will be reflected by any object within above range or suspended object vibration, and the reflected wave will be received by the antenna. The reflected wave will be mixed with original signal to generate a difference-frequency signal. The difference-frequency signal is amplified by an intrusion band-pass filter or an attack band-pass filter. The amplified and filtered signal is sent to two comparator circuits for comparison with a reference signal to generate two driving signals to drive one of the two alarm-generating circuits.

Abstract: A microwave motion sensor for detecting multiple levels of motion of a target is disclosed. The motion sensor includes a transceiver for broadcasting a signal into a predetermined area and receiving a reflected signal with a receiver for producing first and second directional signals. A signal conditioning circuit is provided for amplifying the first and second directional signals and digitizing the directional signals. The signal conditioning circuit includes a micro motion amplifier for separately amplifying one of the directional signals and producing a micro motion signal. A processor is provided for receiving the first and second directional signals transmitted by the signal conditioning circuit, and for receiving the micro motion signal. The processor includes a circuit for analyzing the directional signals, and a circuit for comparing the micro motion signal to a threshold.

Abstract: An intrusion detecting apparatus for a vehicle comprising an ultrasonic transmitting/receiving sensor, an intrusion detecting unit for detecting whether or not a person intrudes into a passenger compartment, based on the received signal, a stopping unit for intermittently stopping the transmission from the transmitter, and a cover detecting unit for detecting whether or not the sensor is covered, based on the signal received after stopping the transmission of the signal and, in response to a predetermined condition representing that the sensor is covered, whereby it can correctly determine whether or not the sensor is covered, improving the accuracy of the detection of an illegal intrusion of a person. At least one of a transmitter and a receiver in the sensor and the intrusion detecting unit is also intermittently operated to reduce the power consumption.

Abstract: An intrusion and alarm sending arrangement having at least one motion sensing device and a first motion signal threshold device has an input connected to said motion sensing device for generating a motion alarm indication in response to a motion signal exceeding a motion threshold determined by said first motion threshold device. At least one infrasonic sensing device is connected to a first infrasonic threshold device having an input connected to said infrasonic sensing device for generating an infrasonic alarm indication in response to an infrasonic signal exceeding an infrasonic threshold determined by said first infrasonic threshold device. A decision device has a motion alarm input and an infrasonic alarm input for respectively receiving said motion alarm indication and said infrasonic alarm indication, and an output, for generating a valid alarm indication upon determining simultaneity of said motion alarm indication and said infrasonic alarm indication.

Abstract: The signal delivered by a Doppler sensor is treated after amplification, filtering and digitization by: means for determining the global energy of the digitized signal; autocorrelation test means for showing up a dominant frequency; a filter for rejecting that frequency; comparators for eliminating signals having energy less than a threshold; a filter for isolating a particular frequency band; and means for intercorrelation with a reference signal held in memory.

Abstract: An apparatus for detecting intrusions into spaces of various kinds such as apartments, offices, lockers, and the like by either authorized or unauthorized persons apparatus monitors a specific portal for intrusion occurrence events using an intrusion sensing unit, which communicates intrusion occurrence information to a remote, and possibly hidden monitor unit. The monitor dynamically counts the number of valid intrusion occurrence signals received from the sensing unit and stores the same in non-volatile memory. The number of intrusions stored in memory can be displayed on a display means at the monitor unit, which, in a simple embodiment would take the form of a single, seven segment light emitting diode (LED) display. In addition, the number of intrusions stored in the non-volatile memory can only be reset by the input of a unique, coded personal identification number (PIN) signal from an input keypad located on the monitor unit.

Abstract: An apparatus and method for varying the sampling frequency of a Doppler effect device, based on environmental conditions, is described comprising: (i) a transmitter for transmitting energy into a protected area; (ii) a receiver for receiving energy reflected from the protected area and for transforming the received energy into a motion detection signal which is proportional to any Doppler energy received by the receiver; (iii) a processor responsive to the motion detection and operative to automatically modify the sampling frequency when the motion detection signal exceeds a predetermined threshold value and the apparatus has not been operated at each of a plurality of sampling frequencies; and (iv) an alarm coupled to the processor activated when the motion detection signal exceeds the predetermined threshold value and the apparatus has been operated at each of the plurality of sampling frequencies.

Abstract: A motion detection and imaging method and device 10 for carrying out the method are provided. The device 10 comprises a housing 12 containing a CCD 18 for providing digital image data, a lens 16 for focusing an image on the CCD 18 and a solid state non-volatile memory 24 for storing the digital image data. In one embodiment, the device includes a motion detector 26 for triggering the storage of the digital data.

Abstract: A device for controlling power to an electrical load. The device has two components: a portable desktop detector unit and an electrical powerstrip. The desktop detector detects the presence of a human in a room and sends signals to the powerstrip to supply power to or withhold power from individual electrical loads connected to the strip. Since the detector is portable, it can be positioned and repositioned at different locations in a room to maximize its ability to detect the presence of a person. The system can also communicate by wireless signals to a wall-mounted control unit to control light fixtures in the room. When used with a wall-mounted control unit, a photo sensor that detects the level of ambient light in a room allows the system to adjust the brightness of lights in the room depending upon the available ambient light level.

Abstract: A microwave intrusion detector is provided with a periodic signal detector that identifies periodic signals not typical of an intrusion and adjusts the alarm threshold in response such identification. The intrusion detector includes an adjustable threshold and a noise compensating circuit that actively adjusts the threshold at a first predetermined rate to mask background noise levels. The periodic signal detector modifies the adjustment, increasing the predetermined rate, when it detects a periodic signal typical of a motor, fan, florescent light or the like. The periodic signal detector also cancels or disables any pending or ongoing alarm to provide sufficient time for the threshold adjustments at the increased rate.

Abstract: A filter for eliminating the effects of fluorescent lights on microwave transceivers uses a digital comb filter to eliminate signals at the AC power line frequency and its harmonics. A preferred embodiment has an A/D converter or sampler for sampling and digitizing an output signal from a microwave transceiver. The digitized signal is processed by a processor which implements the digital comb filter by performing a recursion equation. The inventive filter may also have a selector for selecting the sampling frequency. By selecting a desired sampling frequency, the filter may be easily adapted to filter out a different AC power line frequency. Thus, the inventive filter is easily adaptable for use in different countries having different AC power line frequencies.

Abstract: A dual technology intrusion detection device has a microwave detection sub-system, employing a bent mono-pole as an antenna to generate a symmetrical conically shaped volume of protection. The intrusion detection system also has a passive infrared intrusion detection sub-system, employing a hemispherically shaped fresnel lens having a plurality of lens segments, to detect infrared radiation from a plurality of spaced apart fields of view in a right symmetrical cone. The volume of protection for the infrared intrusion detector and microwave detector substantially coincide. In addition, the microwave detection sub-system employs a single bipolar transistor and a variable trim capacitor to generate the microwave energy and also uses the single bipolar transistor in an autodyne mode to mix the received microwave radiation.

Abstract: It is an object of the invention to provide a vehicle alarm signal generation device which can realize the reduction of the consumption of power without unstabilizing the intruder detect operation. The vehicle alarm signal generation device includes a supersonic sensor which comprises a supersonic transmitter and a supersonic receiver. The supersonic transmitter radiates supersonic waves in the interior of a vehicle and the radiated supersonic waves are received by the supersonic receiver. If any person intrudes on the vehicle interior, then there is produced a difference between the frequencies of the radiated and received supersonic waves due to the Doppler effect generated responsive to the movements of the intruder, so that a beat frequency signal corresponding to the frequency difference is included in a signal received by the supersonic receiver. The beat frequency signal is integrated by an integrating circuit and is then converted into a voltage signal.

Abstract: An intrusion detection device of the dual sensing type has a PIR sensor to generate a PIR signal. The device also has a microwave sensor for generating a microwave amplitude signal. The microwave amplitude signal is filtered to generate a microwave high frequency signal which is the high frequency portion of the microwave amplitude signal. These three signals: PIR signal, microwave amplitude signal, and microwave high frequency signals are amplified and are digitized and are processed to generate an event signal. The event signal is compared to an event threshold signal and an alarm is generated in the event the event signal exceeds the event threshold signal. The event threshold signal represents the threshold to distinguish between a human intruder and an animal intruder.

Abstract: A movement detector includes a transmitter (1) and a receiver (2) of electromagnetic, acoustic or light waves, and a frequency variation demodulator (3) connected to the receiver (2) and adapted to supply a signal which is progressively variable as a function of the movement detected. The movement detector further includes an analog-digital converter (5) which transforms the demodulated signal into a digital signal, a memory (6) connected to the converter (5), and an arrangement for controlling the loading of the memory. The memory (6) continuously makes available information corresponding to a memorized threshold signal. A comparator (8) continuously compares the memorized threshold signal with the signal given off by the demodulator (3) and emits a signal when the former is less than the latter.

Abstract: The microwave section of a dual technology sensor comprising microwave and infrared sections may be periodically tested. This is done by arranging for the output of the microwave section to be monitored at times corresponding to microwave pulses and at times coresponding to no microwave pulses. If the microwave section is operating properly then a difference should be seen in the output between the "pulse" and "no pulse" times. Because this test can involve a change in the average energy output by the microwave section it can also affect the infrared section of the sensor which often inadvertently receives radiation from the microwave source. Thus the infrared section may be tested using this effect.

Abstract: Intrusion into an automotive vehicle interior is detected by passing an airborne acoustic signal through a portion of the vehicle interior when the vehicle security system is active, and by measuring any change in phase in the signal as it passes through the vehicle. The phase of a first frequency component in the signal is sensitive to intrusion into the vehicle, and the phase of a second frequency component is sensitive to false alarm conditions, but is not sensitive to intrusion.

Abstract: A car security system has a proximity sensor such as a radar sensor with variable sensitivity and capable of producing a detection signal upon detecting motion of a person in a monitoring area. A control circuit is provided controls the sensitivity of said proximity sensor. The system also has a monitoring/alarming control circuit for control of predetermined monitoring and alarming control on the basis of the output from the proximity sensor, and alarming devices such as a headlight flash circuit, buzzer and siren for performing a predetermined alarming operation under the control of the monitoring/alarming control circuit. The sensitivity control circuit operates in response to a predetermined operation such as an arming start operation to vary the sensitivity of the proximity sensor so as to automatically set the sensitivity to a first sensitivity level which is the highest level within a range which does not cause the sensor to produce the detection output.

Abstract: A dual sensor intrusion detection system utilizes adaptive sensor detection techniques to reduce false alarms.

Abstract: A security system for a vestibule and, more specifically, a security vestibule is equipped with monitoring devices to monitor the presence of an intruder. The monitoring devices transmit signals to warning devices, such as a speaker which broadcasts an audible message as well as a siren and a flashing light which produce audible and visual signals, respectively, to attract attention exteriorly of the vestibule. The monitoring devices further transmit signals to deterrent devices which disturb or offend the perpetrator. The devices are of the type which disperse foul scents, dispense dyes to mark the perpetrator, disperse water at varying temperatures, and discharge electrical shock.

Abstract: A ceiling sensor designed to interface with the computerized controllers of energy management systems is disclosed. This ceiling sensor is operable to detect motion through the use of a transmitted signal of predetermined frequency which when received has experienced a Doppler shift. Comparison of the received signal with its frequency change to the transmitted signal produces motion detection which when incorporated with an isolated latching relay enables the switching on and off of light, heating, air conditioning or security interfaces. A ceiling sensor is disclosed which is operable to detect the short, quick movements of employees working in a narrow range field of view such as a shop aisle or warehouse corridor. A second ceiling sensor is disclosed which is operable to detect the gross, large movements of employees in a large area such as an open room or warehouse. A method of fabricating a ceiling sensor for a computer controller interface is also described.

Abstract: An intruder detector system such as a microwave fence having a transmitter 10 and receiver 12 produces a signal proportional to the disturbance created by an intruder. The signal is processed by a microwave detector 14 and processor 16 and supplied, as DC voltage output to two channels 18, 20. First channel 18 compares the DC voltage strength to a pre-set value stored in a first threshold detector/comparator 22. On the DC voltage exceeding the pre-set value an alarm relay 24 is actuated causing actuation of an alarm (not shown). Second channel 20 passes the voltage through a first filter 26 which removes high frequency signal variations characteristic of a fast moving intruder. Thus the signal which is compared with a second pre-set value stored in a second threshold detector/comparator 28 relates only to slow moving intruders and the preset value can therefore be set for a lower level of disturbance as would be caused by a crawling human intruder.

Abstract: Both a motion detector and a presence detector receive doppler shifted reflected microwave radiation to detect the passage of a person or an animal in a field of view. The motion sensor is adapted to detect the passage of a person or an animal near a doorway and to actuate the doorway in response thereto, to permit the passage of the person or animal thereto. The presence detector detects "swaying motion" of a person or an animal in a field of view much closer to the location of the sensor as its gain is much lower than that of the motion detection channel. In addition the presence detector is activated only in the event the motion sensor is deactivated. The output signals from the motion sensor and presence sensor are gated through an OR gate and to a timer to activate the door opener.

Abstract: A dual technology sensor which uses both ultrasonic and infrared sensors is disclosed. The electronic circuit of the invention requires detection by both sensors to activate the load. Thus, false triggering will not occur unless the false triggering device both emits heat and moves. The avoid having the motion sensor inadvertently turn off while the person is still present, only one of the infrared and ultrasonic sensors is required to be detecting to maintain the activated state.

Abstract: The direction of motion of objects is sampled to determine, in a manner in which substantially avoids false alarms, whether there is object motion in a direction of interest. Systems employing such sampling methodology generate a warning signal in response to a vehicular traffic condition of interest and include at least a pair of motion detectors. Each motion detector processes motion information bearing signals to determine distance traveled in a predetermined time period to minimize false alarms.

Abstract: A microwave motion-detection system incorporates apparatus for actively supervising the operability of the entire microwave system, from the transceiver component, through the output of its signal processing circuitry. Such supervision apparatus comprises a target simulator which responds to a time-varying electrical signal to cause the transceiver to respond as it does when detecting the type of change in reflected microwave energy normally caused by a target of interest moving in the region under surveillance. Preferably, such target simulator comprises a low-cost, general purpose diode positioned in close proximity to the receiver element of the transceiver, a low-frequency signal generator, and timing and control apparatus for periodically applying the output of the signal generator to such diode. In the event of a failure of any microwave system component during the target simulation operation, the supervision apparatus provides a "trouble" alarm.

Abstract: A portable alarm device for monitoring areas against burglary includes an alarm and a power supply connected to the alarm by an alarm circuit. A reception sensor is connected to a variable preamplifier for varying volumes of the alarm signal in accordance with the size of the area being monitored. The preamplifier is connected to at least one rejector circuit frequency filter for controlling the susceptible frequency range of the alarm trigger signals with a microprocessor connected to the rejector frequency filter to receive and transmit the signal. A signal converter is used to activate the power supply. A push button time switch is connected to the signal converter in order to delay time or readiness of the alarm for operation and the power supply is connected to the alarm through the signal converter by a closed circuit for delivering a constant low-intensity current with intermittent interruption by the signal converter.