Abstract: A stencil for contact printing paste solder onto lead and component pads of the leaded substrate of a SIP is a plate having holes therethrough in the pattern of the pads, a first recess in the solder side of the plate over the area of the plate having component holes, and a second recess in the substrate side of the plate adjacent lead holes that are connected to the second recess by narrow slots dimensioned to receive portions of associated leads. The second recess and lead holes are dimensioned for receiving the lead frame and tines on lead pads. In a printing application, the padded side of the substrate contacts the substrate side of the plate with lead tines on lead pads located in associated lead holes, the thickness of the plate adjacent lead holes being slightly greater than the height that lead tines project above the substrate. The depth of the first recess is selected to make paste solder in component holes adhere to associated component pads when the plate and substrate are separated.

Abstract: A switched DC-to-DC converter in a power supply is powered by input line current from an external power source and driven by voltage pulses from a variable duty cycle pulse width modulator for converting a DC input voltage to a DC supply voltage of a different value that is applied to a load impedance. A comparator monitors the supply voltage for producing an error voltage that biases the modulator for adjusting the width of the voltage pulses, and thus the duty cycle of the converter, for maintaining the supply voltage relatively constant. An RC circuit integrates the voltage pulses for producing an indication of the average value thereof, which is directly related to the value of line current drawn by the converter. When the average value of voltage pulses exceeds a reference voltage, the value of bias voltage is limited for establishing the maximum width of voltage pulses and duty cycle of the converter, and thereby limit the maximum line current drawn by the power supply.

Abstract: A power supply in carrier subscriber terminal equipment includes a switched DC-to-DC converter that is powered by a DC line voltage and driven by a pulse width modulator for producing a first DC voltage on a bus line that powers the modulator and an oscillator which keys the modulator. Circuitry for starting the converter, modulator, and oscillator includes a first transistor and Zener diode that are resistively connected in series across the line voltage for producing a second DC voltage on the Zener, which is less than the first voltage. A second transistor is turned on by the second DC voltage for coupling it to the bus line to initially energize the oscillator and modulator, which then drives the converter to cause it to produce the first voltage on the bus line. A second output of the oscillator is also coupled through a voltage doubler to the first transistor for turning it and the Zener off.

Abstract: An improved edge clip terminal having a first diamond-shaped transition region connecting a plurality of tines, that clip over the edge of a substrate, to a first lead section and having a second diamond-shaped transition region connecting the first lead section to a second lead section. In an assembly, the second lead sections of a plurality of terminals are located in holes in a PC board with the second transition regions resting on the surface of the circuit board. The first lead sections are more narrow than the transition regions and of lengths that are sufficient for preventing solder wicking up them and into the areas of the tines during wave soldering of a circuit board so that a leaded substrate soldered into the circuit board may be tilted without damaging it. In an alternate embodiment of this invention, the lead portion of an edge clip terminal on a substrate has a pair of spaced apart transition regions in it.

Abstract: An integrated current source comprising a discrete resistor having one side thereof electrically connected through a PNP transistor to a first DC supply voltage and through series connected base-emitter diodes of a first pair of NPN transistors to a temperature stable DC supply voltage. The other side of the resistor is electrically connected to ground through series connected base-emitter junctions of a second pair of NPN transistors, with the base emitter junctions of the first and second transistor pairs being poled in opposite directions. The NPN transistors are caused to have collector currents that make the base-emitter junction voltages cancel on opposite sides of the resistor. This causes the temperature stable supply voltage to be established across the resistor in order to set a reference current in it, and in an NPN transistor driving the load, that is substantially constant and independent of temperature.

Abstract: A circuit arrangement for combining a measure of the single phase error for a received data signal in a PSK demodulator with a measure of the direction of rotation of the receive data signal phasor between adjacent sample times for producing a timing phase error signal for controlling the phase of a local clock timing signal in the demodulator. In a demodulator producing a digital word defining differences between the phases of decoded phasors at adjacent sample times, a binary bit D.sub.k of the digital word may define the direction of rotation of the received signal phasor between the adjacent sample times. Sample values of the signal phase error signal in the demodulator are quantized into single binary bits E.sub.k indicating the sense of the signal phase error at sample times. In one circuit arrangement, binary bits E.sub.k and D.sub.k are combined in an exclusive-OR gate for producing a binary timing phase error bit M.sub.k.

Abstract: A tray for holding IC packages including cylindrical cases having preformed leads flared radially outward from the bottom thereof with flat portions of the free ends of leads being in a common plane. The tray comprises a top plate having a plurality of funnel shaped openings in it, a rim around the perimeter of the plate, and a flat bottom. Each opening has a cylindrical bottom portion for receiving a case with leads thereon being located in the flared upper portion of the opening and below the surface of the plate. The top and bottom edges of trays are dimensioned so that the top of a first tray nests inside the bottom of a second tray. By merely turning these nested trays over, packages in openings in the first tray sit with the flat portions of leads on the bottom of the second tray. The rim limits transverse movement of packages set on the plate when the tray is shaken to cause them to fall into associated openings.

Abstract: The first monostable multivibrator of a series connected pair of monostable multivibrators is responsive to each break interval of input dial pulses for establishing a fixed time delay after which the second multivibrator initiates a corrected break interval and starts a first timing capacitor thereof charging at a rate set by a fixed time constant. Each input break interval also causes a capacitor of a second timing circuit to start discharging at a rate set by another fixed time constant, the time that the second capacitor starts discharging being a function of the pulse repetition frequency of input dial pulses. When the charge voltages on the two capacitors are the same values, the output of a comparator resets the second multivibrator to terminate an output break interval so as to cause corrected dial pulses in the output thereof to have a constant percent break.

Abstract: A regulating amplifier circuit with each transistor of a differentially connected pair thereof having a base electrode connected through an associated varistor to a first control transistor, the series combination of each varistor and the control transistor being driven by a variable DC bias voltage. The first control transistor is responsive to a gain control voltage for varying its conduction rate through the varistors and thus the gain of the circuit. A first resistor, the primary conduction path of a second control transistor, and a second resistor are electrically connected in series between a fixed DC supply voltage and a ground reference potential, with the second transistors collector voltage being coupled through an emitter follower as the bias voltage.

Abstract: In a thick film screen printer having a chute that is alternately in a horizontal position for receiving a screened substrate at one location on it and inclined downward to slide the screened substrate onto a conveyor belt, a pair of elongated openings extend through the chute at the one location. The broad side edges of the openings are generally parallel to each other and the direction that substrates slide off the chute. These broad edges are also inclined with respect to the top surface of this chute so the openings generally face toward each other. A stream of air is passed through one and then the other of these openings to alternately move substrates over them toward opposite sides of the chute so that they slide onto different transverse locations on the belt.

Abstract: Rectangularly shaped snapstrates are separated into substrates along kerfs that are parallel to edges thereof by belt and roller flexure forces produced by two belts that are caused to be contiguous over the suspended length of the upper belt by a pressure roller forcing the two belts together at an intermediate point between roller supports for the belts. This produces oppositely facing curvatures in the belts at spaced apart transverse lines thereon which flex snapstrates in opposite directions with a flexure force which is sufficient to separate snapstrates on the lower belt with kerfs facing in the right direction and which is not sufficient to separate snapstrates there with kerfs facing in the wrong direction. In an alternate embodiment, the peripheries of rollers are tapered in vertical sections for separating snapstrates along kerfs oriented at right angles. In a further embodiment, only a single belt with a pressure roller pressing down on it is employed to separate snapstrates.

Abstract: A fixture is provided for holding a hybrid substrate having a plurality of components already soldered to conductive patterns and/or lands on the front side thereof and having fingers of a lead frame pressed over one edge thereof for dip soldering lead frame fingers to lands. The fixture comprises a flat plate having a plurality of titanium clips or hook elements extending below the bottom edge of the plate, assembled hybrid substrates being loaded into the fixture with the base of the lead frame resting on the hooks. Slots cut in the front of the plate define a rib that extends over the length of the plate near the bottom edge. The rib contacts the backside of a substrate to form an air gap that prevents flux and solder wicking up it. A hinged cover rests against components on a substrate to hold the latter in place. Only the hook ends of the titanium clips, the lead frame, and a portion of the substrate adjacent the one edge are dipped into molten solder to solder lead fingers to associated lands.

Abstract: This 8-phase modulator comprises logic circuitry for converting tribits XYZ of input data into binary control signals D1, D2, D3 and D4 according to a prescribed plan, a pair of 4-phase signal generators responsive to associated pairs of control signals, and a signal source producing a pair of equal amplitude carrier signals of the same frequency and of phases which differ by 45.degree. for driving associated ones of the 4-phase generators 45.degree. out-of-phase. Equal amplitude vector signals from the two 4-phase generators are combined to produce a resultant vector signal which individually generates the phasors of an 8-phase signal set.

Abstract: The local battery and elements of a booster circuit of the energy storage-energy discharge type of swinging choke power converter are connected in series in the subscriber's local battery loop of a carrier subscriber station terminal. A smoothing capacitor is connected across the battery and booster circuit elements for providing a loop voltage there that may be greater than a local battery voltage where a subscriber Touch-Tone telephone set is off-hook and sending calling signals. Current in the circuit elements is monitored for controlling the duration of the portion of a cycle of operation of the converter during which energy is stored by the choke and, thus, maximum current drain from the battery. In an alternate embodiment, the smoothing capacitor is connected across only circuit elements.

Abstract: A ringer-power generator circuit is provided in which ring pulses cause positive and negative output voltages of a swinging choke regulator to be alternately connected to one of the tip and ring lines of a handset; and cause a control circuit to be alternately connected to and disconnected from a supply voltage. The control circuit has an RC timing circuit which delays initial turn on of the regulator to prevent bell tapping, and includes a transistor, diodes and timing circuit which control maximum output power and maximum output voltage of the regulator for causing the latter to essentially operate as a voltage limited high impedance source.

Abstract: An AC input signal and a DC supply voltage are applied to a tapped coil having end points from which differential input signals are coupled to a differential variolosser that controls the gain of cascaded differential amplifiers. The two output terminals of the cascaded amplifiers are electrically connected together through a pair of equal valued resistors to provide a DC reference voltage at the junction of the two resistors, where the AC signals cancel. The reference voltage is coupled to one side of a high-gain differential control amplifier and to both sides of a differential half-wave rectifier circuit. One side of the rectifier is also connected to one output of the cascaded amplifiers for detecting an amplified signal there. The detected signal is integrated and coupled to the other side of the control amplifier to produce the control signal which regulates the drive current to and loss presented by the variolosser, and thus the level of the input signals to the cascaded amplifiers.

Abstract: In a carrier subscriber terminal, a voltage regulator converts the line voltage to a relatively uniform operating voltage for driving a power converter that charges a local battery. The control circuit for the converter comprises a programmable unijunction transistor (PUT) Q1 having a gate and anode connected to intermediate points of associated pairs of resistors R1-R2 and R3-R4 that are electrically connected across the line, and having a cathode connected through a first capacitor C1 and associated discharge path to one side of the line. A Zener diode D5 is resistively connected across the line to establish a reference voltage which is connected through a first diode D1 to the PUT anode, through second and third diodes D2 and D3 to the PUT gate, and through only the second diode D2 to a second capacitor C2 of the regulator.

Abstract: A wave solder machine is provided which includes an endless moving mesh belt that is made of a nonsolderable material such as titanium wire. The belt is supported so as to be totally immersed in the solder wave as it passes the latter. This causes the undersides of stuffed printed circuit boards on the belt to be brought into contact with the molten solder. The belt wires preferably have a plurality of projections thereon to support the circuit boards above the major portion of the belt. In another machine, the circuit boards are moved along a plurality of parallel wires that pass through the solder wave. Alternatively, the wires themselves may be moving for carrying circuit boards across the solder wave.

Abstract: A substrate grader accepts or rejects a substrate depending upon the degree of warp and then sorts the accepted substrates according to a dimension thereof. The grader comprises a first plate which is U-shaped and inclined at an acute angle with respect to the horizontal, the two arms of the first plate extending above the base thereof. A first elongated member (or lower guide) that is attached to the front of the base has a straight side which is adjacent to and spaced a short distance away from the opening in the first plate. A second elongated member, that is attached to the back of the free ends of the arms, supports a second plate (or upper guide) thereon which extends between the arms, which has a top surface in a plane containing the top surfaces of the arms and base, and which has a stepped edge in the opening.