Abstract: The present invention is directed toward a new type of ringing interface card which overcomes the inability of known cards for testing multi-party service and which enable a technician to measure the ringing frequency and simultaneously to detect which of the tip and ring conductors receives the ringing signal.

Abstract: Apparatus disposed at location of a key telephone system and associated with the system to produce a substitute signal and a substitute alarm in the presence of a ringing voltage when the system is deactuated. The apparatus comprises: an electrically powered lamp for displaying the substitute signal when a first voltage is applied thereto; an electrically powered device for sounding the substitute alarm when a second voltage is supplied thereto; a second source; and a circuit arrangement coupled to the first and second sources, the line, the lamp and the device. The arrangement, when the system is deactuated in the presence of the ringing voltage, produces the first and second voltages and applies same to the lamp and device respectively to cause the substitute signal to be displayed and the substitute alarm to be sounded.

Abstract: An adjustable two-axis lockable vibration resistant mirror mount assembly with an accuracy of approximately two arc seconds features separately adjustable inner and outer coaxial gimbals having locks which clamp the gimbals in the adjusted position without altering that position. An adjusting screw for each gimbal is mounted on the frame and abuts the respective gimbal offset from its pivotal axis. Diagonally opposed pairs of U-shaped locking clips mounted on the outer gimbal straddle bosses on adjacent parts of the frame and inner gimbal, respectively, and are moved tightly against the bosses in directions parallel to the respective gimbal axes by locking screws to secure the gimbals in relatively fixed positions. After locking, the adjusting screws may be removed from the assembly. The center of the reflective mirror surface lies at the intersection of mutually perpendicular pivot axes with the normal to the mirror surface at its center substantially perpendicular to the pivot axes.

Abstract: An active ultrasonic perimeter intrusion detection system comprises an elongated flexible electret tape capable of being stored on and deployed from a reel or the like and connectable when deployed to a signal generator operating at ultrasonic frequencies and to a receiver having a signal processing and alarm capability. The tape comprises an electret layer sandwiched between relatively fixed and movable conductive strips and lies flat on a surface adjacent to the area to be protected such as the walls or ceiling of a room or the perimeter of a ground area. The movable stip produces a substantially undirectional ultrasonic beam outwardly from the tape and along its length so as to illuminate objects that cross over the tape. This causes a reflection of the ultrasonic signal and doppler shifting of its frequency which is detected by the tape, the output of which passes to the receiver for indicating the intrusion.

Abstract: An optical tracking system for aircraft and the like which measures positional variations of a portion of a laser transmitter pulse train or beam returned from a tracked object to derive error signals for energizing the tracking servo mechanism. In particular, the system detects such beam position change by measuring variations in energy received by a quadrant-segmented photo sensor relative to the sensor axis of symmetry. Compensation for scintillation (variation with time of the spatial intensity distribution) of the return beam due to change in the index of refraction of the atmosphere is achieved, in accordance with the invention, by focusing the return beam to a small diameter and passing it through a diffusing medium such as opal glass or a fiber optic bundle. The energy in the output beam from this medium is homogeneous and substantially invariant with time so that tracking error due to scintillation is eliminated.

Abstract: A system for identifying and locating objects of known chemical composition and discriminating against a background having a different chemical composition comprises a source of radiation for illuminating the object and the background and a receiver responsive solely to the fluorescent radiation from the object. The receiver comprises a filter which passes radiation from the object and a photodetector array which receives the filter output and produces an output containing the coordinates of the location of the received signal or signals on the array. This location information is applied to utilization apparatus which may comprise a marking mechanism which marks the location of the object on the background or automatic tracking apparatus which tracks the object of interest or counter apparatus which identifies the quantity of such objects that are illuminated.The invention also comprehends the method of deriving position data by causing a known substance to fluoresce at wavelengths (centered at .lambda..sub.

Abstract: A phase-locked loop is disclosed having a phase comparator, a switched lowpass filter, a voltage controlled oscillator, a loss of lock detector, and a charging circuit. The switched lowpass filter has two different bandwidths: the first bandwidth has a wide frequency response for use during acquisition periods for rapid acquisition, and a second bandwidth has a very narrow bandwidth for use during normal tracking for tight control of the voltage controlled oscillator. A loss of lock detector controls the particular filter bandwidth state by causing certain filter components to be switched in and out according to the presence or absence of phase lock condition. A charging circuit, used in conjunction with the particular lowpass filter section not operative during acquisition, charges the energy storage components used in this section of the filter to preclude transients from occurring when these components are switched back into the lowpass filter.

Abstract: An active hybrid circuit for providing isolation between a signal receiving line and a signal transmitting line coupled to a two-wire telephone subset. The receiving line is coupled to a receiving amplifier having a differential output coupled to a pair of common terminals. The telephone subset is also connected to the two common terminals. The two common terminals are connected to the two inputs of a transmitting operational amplifier. The transmitting signal line is coupled to the output of the transmitting amplifier. A compensating network is connected between the input to the receiving amplifier and one of the inputs to the transmitting amplifier.

Abstract: A time division multiplex system is provided with a conference link to a common transmission highway. The conference link includes a plurality of incoming conference lines with in-gates disposed therein, and a plurality of outgoing conference lines with respective out-gates disposed therein. A common control containing a cyclic memory controls the in-gates for sequentially connecting the incoming conference lines to the common transmission highway during specific time slots, and controls the out-gates to connect an outgoing conference line to the common highway during a specific time slot to establish the conference connection. Each outgoing conference line is connected to a sample and hold circuit for reconstruction of the sampled signal transmitted thereto from the transmission highway, and thereafter to a common adder before being coupled to the incoming lines of the conference link.An operator's console is provided from which the conference connections are established.