Abstract: Signal recording method and apparatus for efficiently correcting a bit error due to dropout occurred in recording an analog data into a digital data and reproducing the digital data is disclosed. The digital signal converted from the analog signal is divided into a plurality of groups to each of which a parity check bit is added. Record pattern is recorded on a record medium by a recording apparatus in accordance with a regular coding such as FM (frequency modulation) or MFM (modified frequency modulation) coding such that more than one bits in a group are not simultaneously influenced by the dropout, e.g. individual bits in a group are spaced from each other by several tracks. On reproducing, the coded digital signal is decoded into the original digital signal and the dropout is detected utilizing the nature of the regularity of the coding. The parity is checked for each of the groups.

Abstract: A toy vehicle including a chassis member mounting an electric motor and rear wheels driven by the motor is provided. A unitary steering block is pivotally and floatably mounted at a hitching point on the front of the chassis and bears the vehicle front wheels and receptacles for floatably mounting electrical pickups. Mounted within the pick-ups are small springs which insure electrical contact to the track.

Abstract: An intercom system for a key telephone installation which can be expanded and contracted to service a diverse number of subscriber units. The intercom system is expandable on a modular basis of eight subscriber units. The preferred embodiment can service up to forty-eight subscriber units. The intercom hardware includes a single supervision module, at least one signalling module, and one or more station modules. The intercom system provides up to six independent communication links for a forty-eight unit system. The system also provides such features as dial tone, ring-back tone, busy signal, interrupted ringing, and independent ringing. These features are provided by a hardware organization that is both expandable and comparatively inexpensive.

Abstract: A support plate for an electrical connector shell mounted over an opening in the backplate of an avionics rack and panel tray to strengthen the connector shell from bending during insertion of and mating with a removable avionics electronics module. When an avionics module is inserted into the avionics tray, a great deal of force is applied to the connector shell tending to cause it to bend away from the force. This bending is substantially prevented by providing one or more support plates having a transverse plate aligned perpendicularly to the plane of the connector shell. The support plate is mounted on the rear side of the backplate by means of the same bolts used to mount the connector shell. The perpendicular transverse plate has a projection that extends through the opening in the backplate to abut against the rear face of the connector shell midway between its mountings, thereby resisting any rearward bowing or bending of the connector shell.

Abstract: A sensing apparatus having a stationary part and a movable part which rotates in relation to the stationary part, is attached to both a towing and the towed vehicle so that the stationary part is fixedly attached to one vehicle and the movable part is relatively fixedly attached to the other vehicle. The angular relationship between the towing and the towed vehicle is reflected in the angular relationship between the stationary part and the movable part of the sensing apparatus. This angular relationship is electrically sensed and displayed on an indicating device in the towing vehicle.

Abstract: The problem of defaced acoustical ceilings in homes, apartments, offices, etc., is eliminated in a highly simple and economical manner. The ceilings are defaced as the result of the removal of decorative hooks which suspend plants, etc. In accordance with the present method, the unsightly hole and surrounding defaced region are effectively obscured by first removing a circular region of acoustical substance from the underlying wallboard surface, the circular region having as its center the hole formed by the decorative hook. Thereafter, a circular patch of acoustical material is applied to the wallboard surface, completely filling the circular region from which the acoustical material was removed. The result is such that it is difficult to ascertain what part is patched and what part is not.In accordance with the apparatus, a circular patch of acoustical material (or simulated acoustical material) is provided in combination with a tool of corresponding size.

Abstract: A real-time error detection system for bi-phase or similarly encoded digital data is disclosed. Bi-phase or similarly encoded data, which utilizes two transitions in a bit cell for either a binary "1" or a binary "0" value, and one transition in a bit cell for the other binary value inherently generates an even number of transitions of the binary value represented by the two transitions between the occurrence of the other binary value represented by one transition. Monitoring for the number of transitions of the binary value represented by two transitions provides an indication of the occurrence of an odd number of transitions. This represents an error condition. The system utilizes a logic circuit responsive to the binary "1" and binary "0" data clock retrieved from the self-clocking bi-phase encoded data. When an error condition is detected, an error indicating signal is generated.

Abstract: Binary patterns that define alphanumeric characters for display are stored in a character pattern memory in a size that is smaller than the pattern that will be needed for display purposes. Each such stored character pattern is expanded to the size of a display character pattern, at a time when that character is to be displayed, on a point by point basis of the stored pattern. The expansion of each point in a stored character pattern is accomplished by a relationship that takes into consideration the points surrounding the point to be expanded.When a character requires a binary pattern that is not readily susceptible of this type of expansion, the full display size pattern must be stored in memory. This display size pattern is broken up into a plurality of smaller stored patterns and stored in memory as a plurality of adjacent smaller patterns. In effect, then, two different character pattern sizes are stored in memory.

Abstract: A probe head having interface contact members and probe elements on a first side of an insulating support. The interface contact members and the probe elements both pass through the support to a second side where conductors couple interface contact members with appropriate probe elements. A test fixture for using the probe head to test printed circuit boards is also disclosed.

Abstract: A thermometer or bouncing-ball LED display system provides a fast response, easily readable, quantitative indication of a variable. A received analog signal, representing the variable to be displayed, is effectively compared with an analog signal representing the present display indication. The difference therebetween is averaged over a sampling period. If this average difference exceeds a predetermined limit in either a positive or negative direction, the display indication is changed to reflect this difference. The sensitivity of the display can be selectively determined by increasing or decreasing the sampling frequency and the predetermined limit. The display system can be selectively operated in three different response modes. In a fast-attack, slow-release mode, the display indication is changed more rapidly in response to positive direction differences in the compare stage, than in response to negative direction differences.

Abstract: Privacy by way of excluding all other key set talking circuits (T-R) from the seized line in a standard key set or conference key set system is obtained by providing a privacy exclusion circuit at each key set in the system. The exclusion circuit at the key set which seizes a particular T-R line first causes the voltage on the A lead associated with that line to drop below a certain critical value, thereby causing all the other exclusion circuits in all the other key sets to open their respective talking circuits if an attempt is made to access the occupied line. In order to permit other key sets to access the occupied line, the key set first to seize the line can, without relinquishing the line, permit the voltage on the respective A lead to rise above the critical value, permitting another key set access. Upon such access occurring by the other key set all other key sets are again excluded because the voltage on that particular A lead again drops below the critical value.

Abstract: An electrical connector structure is disclosed having low, or zero, insertion force interengaging terminals which do not engage initially as the connector mating portions are moved together, but which are automatically moved into engagement as the mating portions are moved into their fully mated position. This automatic engagement results from a lever, or cam, effect which converts relative telescoping motion of the mating portions into relative lateral motion of the low insertion force terminals therein.

Abstract: A toy three wheeled vehicle includes a retroflex articulated handle. The vehicle comprises a body member having a trapezoidal configuration with two rear wheels mounted on an axle and a front swivel wheel. The articulated handle includes two parts that are pivotally mounted together with one of the parts being, in turn, pivotally mounted to the body member within a recessed storage channel. The articulated handle, when in the retroflexion state, can be stored flush with the surface of the body member. The body member further includes a floor board having a pivotable portion which can be folded back upon itself to provide both an opening for an operator's legs and a seat for the operator.

Abstract: A pressurized hot fluid washer includes a combination pumping unit driven by a closed hydraulic system which applies driving impulse forces to an interlocked liquid pump member and a fuel pump member. The liquid pump and fuel pump are hydraulically interlocked so that when liquid is not being discharged through the cleaning gun, the fuel will definitely be stopped. A static pressure line senses the pressure downstream of the liquid pump and transmits the pressure to one end of a spring biased by-pass spool valve. At a predetermined liquid pressure, the spool valve will sequentially close a hydraulic conduit first to deactivate the fuel pump and then open a by-pass conduit to deactivate the liquid pump member. Thus, both the fuel pump and the liquid pump will be automatically stopped, for example, when the cleaning gun is not being used. In addition, a differential area piston is provided in the hydraulic system between the by-pass spool valve and the fuel pump.

Abstract: A high speed hand held polyphase motor and a control system therefor is disclosed. The motor is of the induction type, designed for use in oral surgery and the like. The control system includes a bridge type inverter having a separate pair of solid state switching devices such as transistors connected in a bridge configuration across a pair of direct current power supply conductors for each phase winding of the motor. A switch control circuit is connected between the solid state switches and a variable frequency clock signal generator for turning the switches of each pair on and off in a given phase sequence to provide three phase current for the motor windings. The speed of the motor is proportional to the clock signal frequency. A voltage regulating circuit is connected between the power supply conductors and a source of direct current voltage to supply a direct current voltage across the supply conductors which varies in accordance with the clock signal frequency over a pre-established range.

Abstract: In a phase-modulated communication system utilizing voice-band communication channels wherein phase-jumps may be experienced, a phase-jump detector indicates the occurrence of such phase-jumps. A phase-jump corrector responds to the persistence of a phase-jump condition by correcting for it without requiring shut-down and complete reequalization of the transmission channel. Monitoring of the incoming signal for phase-jump occurrence provides a convenient signal quality indication that represents the magnitude of the error in the X and Y components of each received symbol.

Abstract: A paper dispensing apparatus includes a base member having a stand and a pair of wheels and a support member attached to the base member. A plurality of shafts extend outward from the support member to respectively support different widths of paper rolls. A handle can be attached to the support member to assist manipulation of the apparatus by an operator. Cutting bars can extend either in a cantilevered fashion adjacent the respective paper rolls or be attached at either end of the respective shaft. A pressure bar can hold the paper roll and assist in applying masking tape from an adjacent masking roll support member. Extension tubes are provided for adjusting the length of a shaft to accommodate a paper roll greater in width than that of the shaft length. As an alternative embodiment, a hand-carried single shaft dispenser is also disclosed.

Abstract: A control tower and track set includes individual track segments and a three-part control tower. The control tower base incorporates a power transmission assembly that is capable of deriving power from a vehicle when it is restrained on the base member. An endless conveyor belt can be driven by the power transmission assembly in either a verticle or horizontal mode of operation. A rotatable control or observation tower is mounted at the top of the control tower and includes a spring-loaded transparent canopy shell that can be activated by the conveyor belt assembly. The individual subcomponents of the control tower can be combined with accessories to form independent toys.

Abstract: An avionic tray is disclosed for supporting electronic instruments on a shelf. The tray includes an aperture formed thereon for providing the supporting instrument with communication to an air plenum chamber. An interchangeable metering plate is adapted to extend over the aperture, with the plate having a predetermined number of metering ports formed thereon in any desired arrangement. The metering plate is interconnected to the aperture by means of a removable annular gasket, which in turn sealingly engages a surface of the electronic instrument. The gasket includes a pair of annular grooves for receiving the peripheral edges of the metering plate and the tray aperture. The gasket is constructed in such a manner that any application of a downward or lateral force on the gasket by the supported instrument causes the metering plate to be forced against the rim of the aperture to tightly hold the portion of the gasket between the two elements and prevent the gasket from becoming disengaged.

Abstract: Disclosed is an automatic data communication system having communicating modems equipped with automatic equalizers. The equalizers respond to a first long equalization sequence automatically transmitted from another modem. In response to that long equalization sequence, the equalizer starts from a preset non-equalized condition and assumes a fully equalized condition. That equalized modem is also capable of automatically transmitting its own long equalization sequence to the other modem. Thereafter, second short equalization sequences are employed at the receiving modems to enable a memory storage associated with the automatic equalizers. The memory stores, in response to the long equalization sequence, signals which are indicative of the fully equalized condition. Accordingly, the equalizers do not have to start from a non-equalized condition for each new data message unless a dramatic distortion occurs.