Abstract: A circuit for monitoring the status of electrical signals, such as those present on the control and data lines of an RS-232 interface, includes a single operational amplifier and a dual-color LED indicator. The electrical characteristics of the LED's form a significant part of the circuit parameters. The monitor design provides a predetermined circuit input impedance and positive/negative switching thresholds to effect the selective illumination of the LED's.

Abstract: A printer system is configured as a kit for retrofitting the input consoles of existing letter sorting machines of the type used by the U.S. Postal Service. Such machines require that an operator, stationed at a console, enter sorting information for each mail piece, by way of a manually actuated keyboard. The present invention expands the processing capabilities of the machines by imprinting machine-readable, coded information on the respective faces of the mail pieces simultaneously with the sorting thereof. At the same time, the printing function does not impair or modify the usual operator-controlled console when mail is processed which does not require such coding.

Abstract: Standard ASCII coded text is divided into alpha, numeric, and punctuation tokens. Each token is converted to a string of four-bit nibbles. One nibble is coded to identify the type of token. Additional nibbles are coded to identify the location, if any, of a corresponding alpha or punctuation token in a global dictionary. If no corresponding alpha token is in the dictionary, an alpha token is divided into prefixed, suffixes, and a stem. The location of any prefixes in a table of prefixes, suffixes in a table of suffixes, and the number, and location of corresponding individual characters in a table, of the remaining stem are then coded and stored as part of the string of four-bit nibbles for the alpha tokens. Numeric tokens are stored as a string of four-bit nibbles in which the first nibble identifies the type of token, the next nibble the length, followed by a nibble for each of the digits.

Abstract: The present disclosure describes an antenna which may be collapsed and stored in a compact configuration and readily released from storage to assume a deployed operative state. More specifically, the antenna is a wire member comprised of a straight section and an integral transverse helical spring section. The antenna lends itself to storage about the axis of a right circular cylinder while permitting full deployment parallel to the longitudinal axis of the latter. This arrangement permits the storage of potential energies of torsion and bending respectively in the helical spring and straight portions of the antenna, and permits continuous motion in these planes to effect antenna erection and deployment.

Abstract: The present disclosure describes an alignment fixture having particular application in surface-mount connector technology. The fixture utilizes a plurality of through-hole connector sections having pins which are retained in holes formed in a plate and which exhibit a predetermined positional tolerance. A plurality of surface-mount connector sections to be mounted adjacently on the edge of a printed circuit board are plugged into mating through-hole connector sections, and positioned with respect to conductive pads on the board surface. In effect, the above-mentioned positional tolerance has been transferred by the fixture to the surface-mount connector sections.

Abstract: The method uses digital data processing means and stored representations of a table of textual block identifiers for locating in a stored textual data base those textual blocks having the best match with a query. Textual block identifiers each provide an indication of a textual block in a stored data base which contains the corresponding word. The method comprises the following steps: A query word is received having representations of a plurality of words to be located in textual blocks in the stored data base. For each of a plurality of the query words, determine a corresponding set of equivalent words which are contained in the stored data base. Each set of equivalent words is equivalent to the corresponding query word. Each equivalent word has a corresponding group of textual block identifiers represented in the stored table.

Abstract: Apparatus and a related method for generating an estimate of the current state of an information source based upon the observed current and previous states of a related signal and on estimates of the effects of noise. The apparatus includes a state change probability matrix defining the probabilities of all possible state changes that the source is capable of assuming, states, a noise model for generating a set of probabilities indicative of the likelihood that an observed value of the signal would have occurred if the source were in each of its possible states, and circuitry for combining the set of probabilities from the noise model with the set of probabilities from the state change matrix, to provide a probability distribution indicative of the current underlying value of the source.

Abstract: A method using a digital data processing system and a query composed of entries locates entries in a stored multiple layer data base. The entries have one or more event types, and the entries of the data base include entries which have either an exact or an inexact match with entries of the query. The query and a first one of the data base layers are processed to form packages having an assigned order. The packages contain representations of event types in a second layer of the data base (entries in the first layer) and representations of the degree of match between the entry in the first layer and an entry of the query. Representations of the packages and representations of entries in a second one of the data base layers are processed to form a degree of match therebetween and to form representations of entries on the second one of the data base layers. For each of individual ones of the entries in the packages, a representation of a further degree of match for such entry is determined and formed.

Abstract: Method and means are disclosed for determining a particular criterion value and an associated positional value for a degree of match between the juxtaposition of a plurality of events of a query and a plurality of events of a stored data base entry. The method and means use a processing means having a plurality of data stores and a temporary store for each data store. Each data store stores a group of data values. The data values are priorly formed and represent the number of event positions between the occurrence of events in the query and the occurrence of the corresponding events in the stored data base. The processing means using the plurality data stores, the temporary stores and the data values stored therein form determined data values and sum-of-distance values which are then used by a utilizing means for in turn deriving a criterion value and a positional value corresponding to the degree of match between the query and the data base.

Abstract: Method and means using order of occurrence of entries and of events within entries for creating a data base and/or for finding a predetermined degree of match between the order of occurrence of events and entries in a request and a stored data base and/or for recreating an input in the original order of occurrence from a data base representing the order of occurrence of entries and events.

Abstract: A ventilated enclosure for shielding electronic equipment from radio frequency energy having a minimum wavelength .lambda. which comprises a metal container forming a fully enclosed volume in which the electronic equipment is mounted. Cooling means, such as a fan, directs air through the volume to cool the equipment. The air enters and leaves the volume through an inlet duct and an outlet duct, respectively. Each duct forms a waveguide having a major cross-sectional dimension less than .lambda./2 and a length of the order of 2 .lambda. or greater.

Abstract: An amplifier circuit having stable performance characteristics over a wide temperature range from approximately 0.degree. C up to as high as approximately 500.degree. C, such as might be encountered in a geothermal borehole. The amplifier utilizes ceramic vacuum tubes connected in directly coupled differential amplifier pairs having a common power supply and a cathode follower output stage. In an alternate embodiment, for operation up to 500.degree. C, positive and negative power supplies are utilized to provide improved gain characteristics, and all electrical connections are made by welding. Resistor elements in this version of the invention are specially heat treated to improve their stability with temperature.

Abstract: A system for effecting the removal of ice from external surfaces of aircraft, and particularly from helicopter rotor blades, by the transmission of microwave electromagnetic energy into the ice so that it functions as a surface waveguide. The system includes a permanent surface waveguide with a dielectric constant close to that of ice, so that a composite surface waveguide is formed. The permanent surface waveguide is formed from a characteristically low-loss material, so that the microwave energy is dissipated as heat primarily in the ice layer, thereby very efficiently melting or heating the ice.

Abstract: A system for detecting ice on exterior surfaces of aircraft by transmitting a relatively low power microwave electromagnetic signal into a dielectric layer functioning as a surface waveguide, and monitoring the signals transmitted into and reflected from the waveguide. The waveguide includes a termination element which is mismatched with the waveguide impedance, resulting in partial or total reflection of the microwave energy from the remote end of the waveguide. As ice builds up on the surface waveguide, the impedance or reflection characteristics of the composite waveguide comprising the ice layer and the permanent surface waveguide give a reliable indication of the presence and location of the ice. The reflection characteristics are conventionally monitored utilizing a dual directional coupler and a reflectometer.

Abstract: Method and apparatus for scrambling and unscrambling television video and audio signals in a subscription television system in which program selections of subscribers are known at a central transmitting site, and control signals encoded into vertical blanking intervals of the video signals are addressed to receivers authorized to receive unscrambled transmissions, to selectively control unscrambling at those receivers. In an unscrambler at each subscriber's receiver, the control signals are decoded, and, if addressed to the particular subscriber's receiver, operate to enable or disable the unscrambler, or to frequently vary its mode of operation, thereby greatly increasing the security of the system and deterring viewing of scrambled transmissions. Video scrambling and unscrambling are effected by inversion of selected horizontal lines of a transmitted television picture, and a technique is disclosed for inversion of alternate groups of equal numbers of line.

Abstract: Method and apparatus for scrambling and unscrambling television video and audio signals in a subscription television system in which program selections of subscribers are known at a central transmitting site, and control signals encoded into vertical blanking intervals of the video signals are addressed to receivers authorized to receive unscrambled transmissions, to selectively control unscrambling at those receivers. In an unscrambler at each subscriber's receiver, the control signals are decoded, and, if addressed to the particular subscriber's receiver, operate to enable or disable the unscrambler, or to frequently vary its mode of operation, thereby greatly increasing the security of the system and deterring viewing of scrambled transmissions.

Abstract: Method and apparatus for scrambling and unscrambling television video and audio signals in a subscription television system in which program selections of subscribers are known at a central transmitting site, and control signals encoded into vertical blanking intervals of the video signals are addressed to receivers authorized to receive unscrambled transmissions, to selectively control unscrambling at those receivers. In an unscrambler at each subscriber's receiver, the control signals are decoded, and, if addressed to the particular subscriber's receiver, operate to enable or disable the unscrambler, or to frequently vary its mode of operation, thereby greatly increasing the security of the system and deterring viewing of scrambled transmissions.