Abstract: Microelectronic, locally-situated circuitry and memories, together with digital displays, are employed for modifying otherwise standard telephone stations so that the telephone stations can be utilized to store digital messages, such as the Caller's telephone number, transmitted by each of a plurality of Callers to an unattended User station. The unattended User station automatically retransmits a received digital message back to the Caller for verification, permitting the Caller to correct any error in the digital message or to send to the User station a verification signal that is also stored. All the stored information is available to the User upon his return, and may be used to automatically dial back the Callers.

Abstract: In a record playback system, which includes a carriage within which a stylus arm is mounted, it is desired to clean the stylus tip from time to time. The apparatus according to the present invention lowers and lifts the stylus so as to effect stylus-record engagement and disengagement and in addition the same apparatus cleans the stylus tip during the lowering-lifting cycle.

Abstract: A phase locked-loop circuit includes a non-linear voltage controlled oscillator ideally producing a desired output frequency as a function of time and a memory producing signals which add to the phase locked-loop phase error feedback signal to correct for the VCO non-linearities. A calibration circuit upon activation is responsive to the phase error feedback signal for altering the contents of the memory such as to reduce or eliminate the phase error.

Abstract: A push-pull amplifier having like conductivity output transistors is driven by a phase-splitter transistor amplifier. The collector load of the phase-splitter includes a diode bridge for establishing the amplifier idling current. One arm of the bridge incorporates the pull-up output transistor base-emitter junction-the current conducted therein being accurately determined by bridge parameters.

Abstract: Video disc stylus holders are designed to provide vertical decoupling of the pickup stylus from the stylus support arm. The compliance designed into the holder gives rise to mechanical resonant modes which affect the recovered signal in the audio range. A rigid damping element secured to the compliant section of the stylus holder by a lossy adhesive or a lossy mass rigidly secured to the compliant section of the stylus holder reduces the amplitude of the resonant modes.

Abstract: A plurality of FET or other amplifiers are connected between respective outputs of an N output port power divider network and respective inputs of an N input power combining network in a variable power amplifier system. A gate bias is selectively supplied to each of the amplifiers which is either at a first value to cause the amplifier to amplify or at a second value to cause the amplifier to be cut off and therefore to not dissipate any DC power. The number of amplifiers receiving the first potential is determinative of the amount of power amplification of the variable power amplifier.

Abstract: A record handling mechanism in a disc record playback system includes a record lifting finger which rises through a slot in the turntable to lift a record against a pair of stops located above a set of record receiving pads. The record receiving pads are then retracted out of the way, and the record lifting finger is lowered to a position below the turntable to transfer the record to the turntable. The operating sequence is reversed to restore the record back on the receiving pads.

Abstract: A sensor for measuring motion past the sensor of a non-magnetic conductive part surrounded by a non-magnetic conductive shield. The sensor consists of a bias magnet and pickup coil located outside the shield. Eddy currents are generated in the part as it moves through the magnetic field of the bias magnet. The eddy currents create an electromagnetic field around the part that penetrates the conductive shield causing the generation of secondary eddy currents in the shield. Secondary electromagnetic fields created by the secondary eddy currents induce a voltage in the pickup coil, a parameter of which is indicative of motion of the part.

Abstract: A method and apparatus for the adaptive equalizing of phase and amplitude distortion in a received signal by an N-stage digital delay line system and comprising the steps of digitally sampling the received signal and advancing each digital sample through successive stages of the N-stage digital delay line, producing a continuously up-dated scaled error signal after each advance of the digital samples in the delay line, multiplying the digital sample in each delay line stage by the scaled error signal after each sampling advance to produce a first scaled signal in each stage, separately accumulating the first scaled signals of each stage after each sampling advance, scaling and accumulating the accumulations of the first scaled signals of each stage after each M accumulations thereof to produce a weighting tap signal for each stage of the delay line, multiplying the received samples by the weighting tap signal of each stage to produce a weighted sampling for each stage, summing the weighted samplings to produc

Abstract: A circuit coupled between an indicating pushbutton panel switch and a software-programmable processor permits program control over the effect of switch actuation and over the illumination of the indicators. The processor can disable the switch function, blanking the indicators; it can accept a manual actuation of the switch, changing the illumination; it can reject as invalid a switch actuation within a multiple-switch field, retaining the current illumination; and it can alter the illumination in the absence of switch actuation. In one embodiment the signals providing the switch and indicator status are channeled into a serial data stream and transferred to the processor input register.

Abstract: The player has a record handling mechanism which consists of a sequencing cam for coordinating the operations of a record lifting finger and a set of record receiving pads. To transfer a record from the record receiving pads to a turntable for playback, the record lifting finger is raised through a slot in the turntable to lift the record to a position above the receiving pads, the receiving pads are retracted out of the way, and then the record lifting finger is withdrawn to a location beneath the turntable to deposit the record on the turntable. To transfer the record back to the record receiving pads for retrieval, the sequence of operations is basically reversed. It is desirable to hold the registration between the turntable slot and the record lifting finger when the player is turned off. To this end a shutoff switch actuating mechanism is provided. When the player is turned off, the sequencing cam is driven in a direction that raises the record lifting finger through the turntable slot.

Abstract: A frequency-modulated continuous-wave (FM-CW) ranging system produces a first signal of frequency corresponding to the measured range of a target which signal is sometimes below a given quality and produces a second signal of frequency corresponding to the measured range of a simulated target of known range. A threshold detector determines when the target signal is above the given quality at which time the period of the first signal is determined from a given cycle thereof while concurrently the period of the second signal is determined from which the range to the target can be computed.

Abstract: A signal processing system for use with a radar ranging system which transmits a radio frequency beam of finite angle to a sloping target of not greater than some known slope and creates from the return signal a beat frequency signal comprising various frequencies corresponding to the various distances from the ranging system to the target. The processing system includes a first tracking bandpass filter which is caused to seek and lock onto the lowest frequency F.sub.L in the beat frequency signal. Given frequency F.sub.L, the angle of the beam and the maximum slope of the target, a theoretical maximum frequency F.sub.X is computed. A second tracking bandpass filter tracks down from frequency F.sub.X to and locks onto frequency F.sub.H, the frequency component in the beat frequency signal associated with the maximum range to the target. From frequencies F.sub.L and F.sub.H and the beam angle, the average range to and/or slope of the target can be computed.

Abstract: An improved automatic gain control system for a frequency modulated television (FM/TV) transmitter transmission system comprising a transmitter for generating and transmitting a television (TV) signal, a satellite repeater, and at least one receiver having a demodulator and which collectively form a transmission path having a certain frequency bandwidth with the transmitter comprising a pre-emphasis circuit for pre-emphasizing the TV signal and an FM circuit for frequency modulating the output of the pre-emphasis circuit. The invention provides a filter located at the transmitter for simulating the filter characteristics of the overall transmission path and responsive to the frequency modulated TV signal generated at the transmitter to produce a control signal in the event the spectrum of the frequency modulated TV signal exceeds the transmission path bandwidth.

Abstract: A cutting stylus is positioned with respect to a metal substrate in order to cut a groove. The cutting stylus is vibrated about a quiescent position in response to a relatively high frequency signal while cutting the groove in order to cut an information track comprising short wavelength modulation of the groove depth. Relative motion is established between the metal substrate and the cutting stylus such that the information track is cut along a spiral path. The relative motion is varied in a predetermined manner as the stylus cuts across the surface of the metal substrate such that the spiral information track is formed having a varying pitch to reduce the formation of damaging ridges on the cutting edge of the stylus.

Abstract: A protective cartridge is provided for a disc record used in an optical playback system. The protective cartridge is provided with finger members to suspend the disc record in the cavity of the cartridge so that the information bearing surfaces of the disc record do not touch the inside surfaces of the cartridge. When the record package is in storage, the finger members are biased to engage the outside rim of the disc record. Tapered pins provided on the optical player disengage the finger members to permit the disc record to rotate in the optical player.

Abstract: A turntable secured to a bearing member is freely rotatable about a support post. The bearing member has radial slots through which the fingers of a segmented spindle protrude. The spindle is axially slidable on the post. A spring is disposed about the post for urging the spindle upward for engagement with the record center hole as a record is placed on the turntable.

Abstract: A cutting stylus adapted for mechanically cutting a deep groove, which may be used in lapping the keel on a playback stylus, is provided. The stylus includes a tapering body, a constricted terminal region and shoulders joining the tapering body and the constricted terminal region. The shape of the constricted terminal region is complementary to the shape of the keel tip on the playback stylus. The terminating portion of the stylus tip has a substantially flat cutting face, a pair of side surfaces extending from the side cutting edges of the cutting face which taper at a slight angle to provide clearance to the side cutting edges, and a bottom surface extending from the bottom cutting edge of the cutting face at an angle which provides relief to the bottom cutting edge.

Abstract: A differential amplifier stage is disclosed which utilizes opposed pairs of complementary transistors. The emitter electrodes of the complementary transistors of each pair are connected via matched resistors. A second matched pair of resistors are connected between the emitter electrodes of the input transistor of each complementary transistor pair. The interconnection of the second match pairs of resistors is connected to the base electrodes of the other transistors of each complementary transistor pair by a diode. A constant bias current is applied to the diode-transistor interconnection to provide current to the second pair of resistors to develop like potentials. These potentials establish floating bias potentials across the matched resistors in the emitter circuits of the complementary transistor pairs and thereby establish bias current in the transistors.

Abstract: A differential current amplifier includes a differential input transistor pair having respective first and second unity gain current mirror amplifiers (CMA) connected in their respective output circuits. The output terminal of the CMA connected in the output circuit of the first transistor of the differential pair is connected to the input terminal of the second transistor of the differential pair. The output terminal of the CMA connected in the output circuit of the second transistor is connected to the input terminal of the first transistor. The current feedback to the input terminals of the differential pair conditions them to be responsive to input signal currents. An amplifier output current can be derived from an additional current output from one of the first and second CMA's, the additional CMA output having a gain of A relative to the unity gain output.