Abstract: A bidirectional amplifier for use in a transmission line, that utilizes a pair of interconnected bridge circuits including isolation transformers and a pair of unidirectional amplifiers. The transmission in each direction uses a single amplifier to amplify the signal for a particular direction of transmission without effecting the other amplifier.

Abstract: A circuit adds and subtracts pulse code modulation (PCM) samples in D2 format. An exponent subtractor determines the difference between exponents of the two PCM samples. A mantissa shifter circuit shifts the mantissa portion of a selected PCM sample to compensate for the difference in the exponents. A mantissa adder circuit adds or subtracts the mantissa portion of the shifted and unshifted PCM samples and a sign generator provides a sign value representative of the resultant added or subtracted PCM samples. A normalizer circuit ensures that the mantissa has a predetermined range of values.

Abstract: A three-port conference circuit for use in a pulse code modulated communication system including a first speaker register including an input connected to a telephone system information memory output and including an output, a second speaker register including an input connected to the telephone system information memory output and including an output and a conference adder connected to the first and second speaker register outputs via inputs and including an output connected to a sample inverting circuit of the telephone system. The conference adder adds talking samples by means of an included eight-bit floating point adder.

Abstract: A digital multifrequency receiver circuit of the type employed between telephone system central offices, arranged to provide a faster response to received signals by processing the received signal tones digitally. The faster response resulting from the elimination of automatic gain control circuits and the use of a fixed gain amplifier used only when the received signal is below an acceptable level and the provision of a variable threshold to the individual frequency comparator circuits.

Abstract: A touch probe for detecting contact with a workpiece or other object is disclosed on features a repositionable disc protective shield for the moveable portion of the touch probe. The shield includes a predetermined rest position while providing freedom of movement for the moveable portion.

Abstract: A phase comparator is included with each incoming channel to compare the clock phase of the incoming signal and a local oscillator. The phase comparator of an on-line active unit generates a signal to control the oscillator to maintain its output in phase with the incoming signal. The generated control signal is also connected to capacitor storage in associated channel phase comparators to provide them with an initial starting control voltage when they are switched in to be the receiving channels. Thus eliminating the uncontrolled operation of the oscillator during switching interval.

Abstract: A level comparator is used to check the incoming message header pulse amplitude and if it is of a level higher than an established level a signal is transmitted to update a digital counter whose digital output is converted by a digital to analog converter to establish an increased analog reference level. If the incoming message header is lower the counter is decremented to establish a lower reference level. Then the levels of any signals present at fixed intervals after the header or sync pulse are measured and recorded. These measured levels constitute the value of correction required for subsequent pulses and are added to or subtracted from following data pulses as required.

Abstract: A circuit arranged to measure and correct for transmission line induced disturbances at discrete intervals after receipt of a header pulse by recording the presence of any voltage deviating from a set level. These levels are registered and during receipt of the data pulses are utilized at times corresponding to the relative position of the preceding data pulses to modify subsequent data bits.

Abstract: A leadless ceramic chip carrier for surface mounting on an epoxy printed circuit board is shown featuring an arrangement for relieving the thermally induced stress by progressively lengthening the attaching solder pillars as the distance from the center line of the ceramic chip increases to avoid exceeding the elastic limits of the solder.

Abstract: An apparatus for controlling the charge rate and voltage of storage batteries of a solar power generating system using a single voltage regulator module to monitor and control the state of charge of any number of cells of a battery and a number of solar modules.

Abstract: An electrical connector having a base portion duplicating a printed circuit card edge having thereon contacts for mating with a card jack to which is mounted a printed circuit card jack on the edge away from the contact surfaces. The card edge connector portion is plugged into a card jack of a test apparatus after which the attached card jack is the jack into which cards to be tested are inserted.

Abstract: A two amplifier subscriber line interface circuit that uses a novel voltage divider technique for providing power to the two lower voltage amplifiers from a 50 volt central office battery. This is achieved by using one lower power amplifier with a Zener regulator diode in shunt thereof to regulate its current.

Abstract: An alarm apparatus for use with a numerically controlled twisted pair wire wrap wiring machine that indicates to the operator the position and the wire of a pair that is to be wired. The apparatus is connected to the indicator lights of the machine and to the wiring gun to sense the gun placement on the pin. The proper conditions are logically combined, should a condition be changed as by placing a signal wire on a grounded pin an alarm is sounded.

Abstract: A cutting tool with precisely adjustable disposable cutting inserts. In the preferred embodiment of a face milling cutter, the tool utilizes insert holding cartridges mounted in cavities spaced about the periphery of the cutter body, each cartridge including an insert mounting pocket for presenting each insert such that its cutting portion extends beyond a face of the cutter body. The insert mounting portion of each cartridge is rendered flexible by a slot in the cartridge body. A wedge mechanism adjacent each cartridge causes the cartridge to bend in a manner such that the insert cutting tip will traverse an arcuate path thereby finally and precisely varying the extent to which the cutting portion of the insert extends beyond the cutter body face.

Abstract: An arrangement for automatically testing a plurality of subscriber lines, which are operationally connected to an electromechanical switching system is shown. Operational service is to be transferred from the electromechanical switching system to a digital switching system. This arrangement provides for automatically verifying whether the digital switching system is arranged to apply the proper ringing signal to each subscriber by a comparison with that applied by the electromechanical switching system.

Abstract: A method and apparatus for limiting the interference caused by shadows of minute particles of opaque matter that settles on the surface of an assembly of a metal substrate, a resist and an overlay by placing a second glass overlay on top of the assembly to raise the surface to a level where the shadows of any particles resting there will be diffused.

Abstract: A tool for facilitating the insertion of miniature cable connectors into mating receptacles from both top and bottom. The bottom includes guide arms to maintain the contact pins in proper alignment until entry into a mating receptacle is made.

Abstract: An arrangement for monitoring the admittance of a line during a frequency sweep is disclosed which upon detection of the characteristic admittance level determines the loaded or unloaded status of a transmission line. Output logic associated with detection circuits provides a digital indication of the status detected.

Abstract: A circuit for increasing the inductance of a transformer as used in a telephone line circuit. An operational amplifier with appropriate feedback is connected across a separate winding of the transformer to provide the reactive inductance. To compensate for changes in resistance of the winding, a field effect transistor is controlled by the same amplifier output to provide a positive resistance in the feedback path and thus maintain balance. An operational amplifier and diode are arranged to cooperate with the negative inductor to prevent lock-up.

Abstract: A circuit for increasing the inductance of a transformer as used in a telephone line circuit. An operational amplifier with appropriate feedback is connected across a separate winding of the transformer to provide the reactive inductance. To compensate for changes in resistance of the winding, a field effect transistor is controlled by the same amplifier output to provide a positive resistance in the feedback path and thus maintain balance.