Abstract: An audio signal enhancement system having a digital interface for transmitting a digital audio signal obtained from a digital storage device. The system includes a digital-to-analog converter connected to the digital interface for receiving the digital audio signal and converting it to an analog signal. An analog gain stage is connected to the digital-to-analog converter which includes at least one vacuum tube through which the analog signal is passed, whereby to amplify the analog signal and to impart enhanced euphonic characteristics to the analog signal.

Abstract: A fire event detection system includes a programmable logic circuit which evaluates electrical resistance input data and energizes an alarm upon programmed conditions. The system includes a temperature sensitive polymeric tape spanning between a pair of conductors connected to the circuit. The conductors and tape define a plurality of notches for redirecting current transversely across the tape between the for enhancing responsiveness to a temperature increase at a particular location along the tape. The circuit energizes the alarm if the resistance data indicates a temperature greater than a predetermined critical temperature parameter or if the data indicates a temperature rate of rise greater than a critical rate of rise parameter. The tape may include notched and unnotched portions such that the circuit energizes the alarm if the rate of rise at a particular location is greater than the rate of rise of the tape as a whole.

Abstract: A sleep alarm for use in a vehicle for detecting the condition indicative of the onset of sleepiness of a driver and for alerting the driver thereto comprises first and second conductive elements attached in spaced apart relationship to opposite sides of a steering wheel rim. The first conductive element is electrically grounded while the second conductive element is connected to a voltage source. The conductive elements are positioned such that the fingertips of a driver's hand will make proximate contact with the second conductive element. A monitoring circuit is electrically coupled to the second conductive element for sensing the capacitance of the second conductive element relative to the first grounded conductive element.