Abstract: A control circuit 16 that is responsive to voltage conditions on a cable pair transmission line for selectively disabling a battey charging circuit 12 operating off of line current comprises a resistor R5 and storage capacitor C2 connected in series across the line; a timing capacitor C1 connected between the cathode of a PUT (programmable unijunction transistor) and one wire 32 of the line; and a zener diode D1 between the PUT anode and one wire 32 for establishing a conduction threshold for the PUT. The resistor R5 and primary conduction path of a first bipolar transistor Q2, having its base connected to the PUT anode, are connected in series between the other wire 33 of the line and the charging circuit so that startup current for the charging circuit may be used for charging C2 when the charging circuit is disabled. Means is also included for driving the PUT gate voltage low and turning on the PUT in response to both high and low voltage conditions on the line.

Abstract: An integratable circuit that simulates a source resistor comprises first and second nodes for connection to a voltage source and a virtual ground, respectively; a first integrated capacitor C1; and switch means operative for alternately electrically connecting C1's top and bottom plates to the first node and ground, respectively, and to ground and the second node, respectively, during first and second non-overlapping time periods in each time interval T for charging C1 to the source voltage and discharging C1 into the second node, respectively, where T is the time interval between adjacent second time periods and f=1/T is the switching frequency for C1.

Abstract: A control circuit 16 that is responsive to voltage conditions on a cable pair transmission line for selectively disabling a battery charging circuit 12 operating off of line current comprises a resistor R5 and storage capacitor C2 connected in series across the line; a timing capacitor C1 connected between the cathode of a PUT (programmable unijunction transistor) and one wire 32 of the line; and a zener diode D1 between the PUT anode and one wire 32 for establishing a conduction threshold for the PUT. The resistor R5 and primary conduction path of a first bipolar transistor Q2, having its base connected to the PUT anode, are connected in series between the other wire 33 of the line and the charging circuit so that startup current for the charging circuit may be used for charging C2 when the charging circuit is disabled. Means is also included for driving the PUT gate voltage low and turning on the PUT in response to both high and low voltage conditions on the line.

Abstract: A small amount of light that is transmitted in one of a pair of optical fibers having cleaved ends thereof loosely brought into butt contact is converted to leaky modes in the other fiber. Leaky mode light that is radiated out of the perimeter of the other fiber is collected in an integrating enclosure located proximate its one end and extending over a limited length of the other fiber. The light in the enclosure is detected for producing a measure of the degree of alignment of the adjacent ends of the fibers. After the cleaved ends of the fibers are aligned with micromanipulators so as to null the intensity of detected leaky mode radiation, an electrical arc is created across them for permanently joining the fiber ends together in a splice. The integrity of the resultant splice is determined by producing a measure of the splice loss 10 log (1-P.sub.R /P.sub.O), where P.sub.

Abstract: Stacked leaded hybrid substrates and associated carrier plates are exited from a reflow solder operation onto a vibrating table. Vibration of the table sequentially advances each stacked carrier and substrate until components on the latter contact an arm that is spaced above the table. Detection of the presence of a substrate and carrier adjacent the arm causes a plunger to move transversely across the table and into contact with an edge of the substrate. Further movement of the plunger pushes an edge of the carrier into contact with spring loaded pins in the table top. The shear force created on contiguous surfaces of the substrate and carrier by the plunger and pins causes the substrate to slide off of the carrier and over the pins. If this shear force exceeds a prescribed value, the pins rotate into the table top for passing a carrier and/or substrate without damaging the latter.

Abstract: Apparatus for field measurement of the insertion loss of a splice between one ends of first and second optical fibers comprises an integrating sphere that is split along its axis and which has a fiber input port, a pair of spaced-apart padded holes on the axis for receiving associated fibers so as to center the splice inside the sphere, and an output port receiving one end of a fiber bundle which couples diffuse light in the sphere to a radiometer. A baffle plate in the sphere prevents light rays from the splice being incident on the output port. The splice loss is determined by inserting the one end of the first fiber into the input port, with the other end illuminated by light from a source, and reading a reference level of light coupled to the radiometer. The two fibers are then spliced together and the splice located inside the sphere.

Abstract: An integrated circuit comprising first and second nodes that are connected to external circuitry, a voltage follower having input and output terminals electrically connected between the second node and the bottom plate of a first integrated capacitor C1, and second and third integrated capacitors C2 and C3 having the bottom plates thereof connected to a ground reference potential. A switch means is operative for periodically electrically connecting the top plate of C1 to the first and second nodes during first and second non-overlapping time periods in each time interval T for discharging C1 and charging C1 to the difference voltage across the nodes, respectively, where T is the time interval between adjacent second time periods and f=1/T is the switching frequency for C1. The switch means also operates for periodically electrically connecting the top plates of C2 and C3 to the second and first nodes.

Abstract: In an amplifier station for a trunk system, switching apparatus responsive to the absence or presence of a control signal selectively passes R. F. signals in a prescribed frequency band on a main transmission line to first and second lines. During normal operation of the amplifier relay coils are energized so as to engage second and third contacts for passing signals on the second line with amplification. When the amplifier is operating properly, PIN diodes short opposite ends of the first line for improving isolation in the station equipment. In the event of amplifier malfunction, first and third contacts are engaged thereby providing transmission along the first line. A tubular conductive member surrounds the switch contacts so as to provide capacitive coupling thereto. The tubular member is capacitively coupled to a ground plane to thereby by-pass signals which are above the desired passband of the trunk system.

Abstract: This simulation circuit is a one-port network having a pair of nodes connected to inputs of first and second voltage followers that have associated switched capacitors alternately connected across them for being discharged and connected to an integrator for being charged to the output voltage on the latter. A third switched capacitor is alternately connected in series with the voltage follower outputs for sensing the input voltage applied to the nodes, and connected to the integrator where the input voltage is integrated and transferred to the first and second switched capacitors. A floating inductance L=T.sup.2 C4/C1C3 is simulated across the nodes, where T is the reciprocal of the switching frequency, C1, C2 and C3 are the capacitances of associated switched capacitors, C1=C2, C4 is the capacitance in the integrator, and the circuit is characterized by the LDI transformation.

Abstract: An integratable switched capacitor simulation circuit comprising an integrated capacitor C3 having bottom and top plates thereof electrically connected to first and second nodes, and a pair of integrated capacitors C1 and C2 having their top plates electrically connected together. The bottom plate of C2 is electrically connected to the output of a voltage follower that has its input terminal connected to the second node. A first switch means periodically connects the top plates of C1 and C2 to the first and second nodes at a prescribed rate. When the first node is connected to a voltage source and the bottom plate of C1 is connected to either ground or the first node, the circuit simulates a source resistor across the nodes. When the first node and bottom plate of C1 are connected to ground, the circuit simulates a grounded resistor. In alternate embodiments, the capacitances of C1 and/or C3 may be zero valued for presenting an open circuit across the terminals thereof.

Abstract: Sinusoidal timing reference signals, each of which is associated with a different suppresed-sync scrambled-priority television channel signal, frequency modulate associated carrier frequency signals for producing modulated carrier signals that are combined with a continuous wave (CW) sinusoidal carrier frequency signal. After low-pass filtering to block harmonic frequencies that may interfere with the video carriers of composite television signals, only the fundamentals of the CW and modulated carrier signals are combined with non-scrambled and/or scrambled composite television signals for transmission to subscriber's equipment. In a descrambler at a subscriber location, the CW carrier signal is mixed with the modulated carrier signals to produce frequency modulated IF signals containing timing information for associated priority television channel signals.

Abstract: Stacked leaded hybrid substrates and associated carrier plates are exited from a reflow solder operation onto a vibrating table. Vibration of the table sequentially advances each stacked carrier and substrate until components on the latter contact an arm that is spaced above the table. Detection of the presence of a substrate and carrier adjacent the arm causes a plunger to move transversely across the table and into contact with an edge of the substrate. Further movement of the plunger pushes an edge of the carrier into contact with spring loaded pins in the table top. The shear force created on contiguous surfaces of the substrate and carrier by the plunger and pins causes the substrate to slide off the carrier and over the pins. If this shear force exceeds a prescribed value, the pins rotate into the table top for passing a carrier and/or substrate without damaging the latter.

Abstract: During scribing of a ceramic plate with a laser beam, ceramic particles rise from the workpiece in a direction of motion that is generally the same as that of the workpiece. The lens on a laser scriber is protected from abrasive contact with such particulates in the atmosphere by slipping the base of a housing over the circumference of the lens mount and forming a generally airtight seal between them. The housing is shaped like a frustum of a right circular cone, with the apex end thereof truncated and essentially rolled over to form an orifice through which the lens axis and laser beam pass. A plurality of streams of pressurized air are introduced into the housing near the midpoint of the frustum and the lens surface. The air streams are introduced tangent to the inner surface of the housing and angled downward for producing a vortex of air that is exhausted to the atmosphere through the orifice at a velocity and vorticity that inhibits particulates outside of the cover entering the orifice.

Abstract: The base electrode of the switching transistor in a converter is resistively connected to the output terminal of a pulse width modulator and connected through first and second series connected diodes to a ground reference potential which is also connected to the emitter of the transistor, the junction between the diodes being electrically connected through a large capacitor to the modulator output terminal. Voltage pulses at the output terminal cause the transistor to pass collector current and the second diode to conduct for charging the capacitor. On termination of voltage pulses, the modulator connects the output terminal thereof to ground. This causes the charge voltage on the capacitor to turn the first diode on to pull the base voltage sharply negative for rapidly drawing minority carriers out of the base region.

Abstract: Paste solder is contact printed onto lead and component pads of a leaded hybrid substrate through holes that are arranged in a plate in the pattern of the pads, a first recess in the solder or top side of the plate extending over the area containing component holes. In order to accommodate lead frames of single in-line packages (SIP), a second recess is formed in the bottom or substrate side of the plate adjacent lead holes that are defined by a plate thickness that is slightly greater than the height of lead tines located on lead pads. In a printing operation, the bottom of the plate is moved into contact with the padded side of the substrate of a SIP, with lead tines on lead pads being located in associated lead holes and the lead frame in the second recess. Paste solder is then squeegeed over the top of the plate for printing solder onto the component and lead pads of the substrate in a single printing operation.

Abstract: A tactile matrix switch has a planar electrically conductive layer dielectrically spaced between contacts of individual switch elements and an actuating mechanism such as a finger on the body of a human being who may carry an electrostatic charge. Some switch contacts are electrically connected through external circuitry to ground. The conductive layer is also electrically connected to ground. When a human operator carrying an electrostatic charge brings his finger near the face of the matrix switch for applying a tactile force to actuate an individual switch element, the conductive layer electrically conducts the electrostatic charge to ground and away from the switch contacts for protecting the electrical circuitry connected to the latter. In one embodiment, the conductive layer is electrically conductive printer's ink, having a resistivity of less than 50 k ohms per square, that is silk screened onto the back of a face plate of the matrix switch.

Abstract: During scribing of a ceramic plate with a laser beam, ceramic particles rise from the workpiece in a direction of motion that is generally the same as that of the workpiece. The lens on a laser scriber is protected from abrasive contact with such particulates in the atmosphere by slipping the base of a housing over the circumference of the lens mount and forming a generally airtight seal between them. The housing is shaped like a frustum of a right circular cone, with the apex end thereof truncated and essentially rolled over to form an orifice through which the lens axis and laser beam pass. A plurality of streams of pressurized air are introduced into the housing near the midpoint of the frustum and the lens surface. The air streams are introduced tangent to the inner surface of the housing and angled downward for producing a vortex of air that is exhausted to the atmosphere through the orifice at a velocity and vorticity that inhibits particulates outside of the cover entering the orifice.

Abstract: A two terminal circuit comprising a capacitive element (with a negative capacitance of value -C/2) connected between the terminals, and an integrated capacitor (with a positive capacitance C) having one and other sides thereof alternately or periodically connected to associated sides of the element and to ground for simulating a floating bilinear resistor having a resistance R=T/C across the terminals which satifies the bilinear transformation s=(2(z-1/T)z+1). This circuit is insensitive to both top and bottom plate parasitic capacitance effects assocated with the capacitance when one terminal is connected to a voltage source and the other to a virtual ground point on the input to an operational amplifier. In alternate embodiments, the circuit simulates a grounded bilinear resistor when only one of the terminals is connected to ground, and when one terminal and one side of the capacitor are grounded.

Abstract: In this method of fabricating an electrical circuit assembly, a thick film hybrid substrate is held in an inverted position as apertured glass-ceramic beads are placed over the end leads on the substrate. A drop of liquid flux is then applied to the apertures to hold the beads in place. After the flux dries, the leads are inserted into plated-through holes in a circuit board, with the beads locating portions of the leads above the board. Following wave soldering of the board, the beads are fractured with a sharp instrument prior to a cleaning operation which removes bead parts from the soldered assembly. In this manner, the substrate is flexibly mounted in the board so that the substrate can be tilted without damaging it.

Abstract: A -DC to +DC voltage converter having one input and one output terminal connected to ground and regulator circuitry responsive to a control voltage for regulating the magnitude of output current delivered to a load impedance connected across the output terminals. Apparatus producing the control voltage comprises a passive resistive bridge circuit having one pair of nodes connected between the other input and other output terminals and a current sensing resistor in one arm of the bridge so as to pass load current to the other output terminal, a difference voltage that is the control voltage being developed between the second pair of nodes of the bridge. In one embodiment, the bridge comprises a potentiometer having a moveable contact connected to the other input terminal, and first and second pairs of series connected resistors connected between opposite sides of the potentiometer and opposite sides of the current sensing resistor.