Abstract: A detection system for identifying deterioration in a structure is provided that has acoustic sensors that receive acoustic emission waves. The acoustic emission wave detected by the acoustic sensor is identified as a hit. An analysis circuit is present that identifies an A state, a B state, and a C state. The B state has increased hit activity from the A state where a rate B is greater than a rate A by a factor of f1. The C state has increased hit activity from the B state where a rate C is greater than the rate A by a factor of f2. An alarm is activated when an amount of time that the C state is identified as being present reaches a value of TM, or alternatively when a threshold value based upon of the number of hits and time in the C state is reached.

Abstract: A detection system for identifying deterioration in a structure is provided that has acoustic sensors that receive acoustic emission waves. The acoustic emission wave detected by the acoustic sensor is identified as a hit. An analysis circuit is present that identifies an A state, a B state, and a C state. The B state has increased hit activity from the A state where a rate B is greater than a rate A by a factor of f1. The C state has increased hit activity from the B state where a rate C is greater than the rate A by a factor of f2. An alarm is activated when an amount of time that the C state is identified as being present reaches a value of TM, or alternatively when a threshold value based upon of the number of hits and time in the C state is reached.

Abstract: A detection and alarm system comprises a piezoelectric film sensor and associated circuitry. The sensor detects acoustic emission signals from metallic objects under stress upon which it is affixed. The associated circuitry receives electronic signals from the sensor, creates and evaluates a sensor output value including rate ratio and frequency content of such signals within preset time limits. This data allows the detection of impending failure, an alarm condition, of the metallic object by identifying significant changes in the rate of emission of such sensor signals. An alarm condition may then trigger an alarm signal to warn of such impending failure.

Abstract: A detection and alarm system comprises a piezoelectric film sensor and associated circuitry. The sensor detects acoustic emission signals from metallic objects under stress upon which it is affixed. The associated circuitry receives electronic signals from the sensor, creates and evaluates a sensor output value including rate ratio and frequency content of such signals within preset time limits. This data allows the detection of impending failure, an alarm condition, of the metallic object by identifying significant changes in the rate of emission of such sensor signals. An alarm condition may then trigger an alarm signal to warn of such impending failure.

Abstract: A method and system for communication within an energy-transmission-limited environment. RF transceivers throughout the site are located site-wide such that areas within the site in which communications are desired are within range of at least one of the RF transceivers. At each location RF transceivers are connected to a control unit. The control unit provides power to the transceivers and allows bi-directional communication of audio/voice and/or digital information. The control units may be networked to each other using standard network type category-5 or equivalent cables and may communicate to one another via the network connection. The control units may also be networked via an alternating current powerline by using an alternating current modem. The transceiver of the present invention utilizes single sideband modulators to modulate voice and/or digital signals. The signals are demodulated and filtered at a receiving end of the transceiver. A comb filter attenuates noisy signals with drifting harmonics.

Abstract: A method and system for communication within an energy-transmission-limited environment. RF transceivers throughout the site are located site-wide such that areas within the site in which communications are desired are within range of at least one of the RF transceivers. At each location RF transceivers are connected to a control unit. The control unit provides power to the transceivers and allows bi-directional communication of audio/voice and/or digital information. The control units may be networked to each other using standard network type category-5 or equivalent cables and may communicate to one another via the network connection. The control units may also be networked via an alternating current powerline by using an alternating current modem. The transceiver of the present invention utilizes single sideband modulators to modulate voice and/or digital signals. The signals are demodulated and filtered at a receiving end of the transceiver. A comb filter attenuates noisy signals with drifting harmonics.

Abstract: A method and system for communication within an energy-transmission-limited environment. RF transceivers throughout the site are located site-wide such that areas within the site in which communications are desired are within range of at least one of the RF transceivers. At each location RF transceivers are connected to a control unit. The control unit provides power to the transceivers and allows bi-directional communication of audio/voice and/or digital information. The control units may be networked to each other using standard network type category-5 or equivalent cables and may communicate to one another via the network connection. The control units may also be networked via an alternating current powerline by using an alternating current modem. The transceiver of the present invention utilizes single sideband modulators to modulate voice and/or digital signals. The signals are demodulated and filtered at a receiving end of the transceiver. A comb filter attenuates noisy signals with drifting harmonics.

Abstract: A method and system for communication within an energy-transmission-limited environment. RF transceivers throughout the site are located site-wide such that areas within the site in which communications are desired are within range of at least one of the RF transceivers. At each location RF transceivers are connected to a control unit. The control unit provides power to the transceivers and allows bi-directional communication of audio/voice and/or digital information. The control units may be networked to each other using standard network type category-5 or equivalent cables and may communicate to one another via the network connection. The control units may also be networked via an alternating current powerline by using an alternating current modem. The transceiver of the present invention utilizes single sideband modulators to modulate voice and/or digital signals. The signals are demodulated and filtered at a receiving end of the transceiver. A comb filter attenuates noisy signals with drifting harmonics.

Abstract: A personal security alarm system which activates audible and visible alarms instantly at the location of an emergency, and simultaneously notifies security personnel of the existence and location of the emergency so that response to the call for help can be immediate. When a person is threatened, the person actuates a hand-held alarm actuator-transmitter by pressing a pushbutton. The signal is received by an area relay receiver which triggers an alarm at the location where the incident is occurring. At the same time the area relay receiver relays the state of emergency to a master computer which identifies the area relay receiver activated by the hand-held alarm actuator-transmitter. The master computer activates an annunciator and displays on a color video screen graphically and in print the floor plan or the site layout where the incident is occurring. A portable device is provided for resetting the portable alarm activator.

Abstract: The present invention provides an improved electronic parking system which has the capability of providing a relatively inexpensive personal security system to better protect patrons while in the parking garage. The invention provides increased protection through the use of a portable and convenient transmitter carried by a patron which activates a receiver-relay to summon help and activates horns and sirens to frighten away an attacker. The response of the system is immediate and does not depend on visual or auditory interpretation.

Abstract: A method and apparatus for transmitting and receiving messages by electromagnetic induction in a power restricted environment is disclosed in which the message bandwidth is narrowed prior to transmission and restored to its original breadth upon reception. This is accomplished by imputting a signal of a given duration into a signal storage means and outputting the signal from the storage means over a longer duration. The signal must be converted into a form suitable for storage. In a first preferred embodiment this is accomplished by converting the message to a digital form inputting it into a signal storage means, retrieving the message from storage at a rate different from the input rate and converting the retrived message to analog form. In a second preferred embodiment the signal is differentiated, and converted into a square wave; the zero crossings are identified and stored.

Abstract: Improved discontinuous and cermet film resistors and strain gauges are disclosed wherein the film is maintained in a constant humidity in the range of 15% to 45% thereby substantially increasing the stable life of the strain gauge.

Abstract: An improved discontinuous film resistor and strain gauge is disclosed wherein the discontinuous metal film is maintained in a constant humidity in the range of 15% to 45% thereby substantially increasing the life of the strain gauge.

Abstract: The specification discloses a solar cell having a graded band gap and a plurality of alternately active and inactive p-n junctions. The cell has a gradually changing monocrystalline structure of IIIA-VA compounds. The graded band gaps of the cell are the result of the gradually changing chemical composition of the cell's monocrystalline structure. The junctions are produced by conventional doping techniques.