Showing papers on "Division (mathematics) published in 1968"

A Division Algorithm for Signed-Digit Arithmetic

Abstract: —The application of a fast division algorithm, particu-larly suitable for floating-point arithmetic, to signed-digit number systems is described. This method, based on the method of A. Svo-boda, is performed in two steps: 1) the divisor is adjusted to be of the form (1+e) where e is a fractional quantity, while the dividend is adjusted accordingly, and 2) the generation of each quotient digit is determined by only one digit in the partial remainder together with the transfer digit (or carry/borrow) emanating from it. A working example of radix 16 is given.

The Absolute Thermoelectric Powers of the Liquid Alkali Metals

Abstract: Data are presented on the absolute thermoelectric powers of the alkali metals, including the changes at the melting points, and a short discussion is given on the extent to which experiment and theory are now in agreement. The author is also grateful to A. S. Marwaha for many helpful discussions and to J. W. Harrison of the Metallurgy Division, Harwell, for providing the computer programme.

Time division multiplex system

Abstract: A time division multiplex system is described wherein several data input sources which run asynchronously are multiplexed onto a common link or line, together with coordination data to insure a synchronous flow of data into the line. The coordination data is used upon demultiplexing to control the rate at which demultiplexing is accomplished in order to keep the average rate of data flow through the system approximately constant.

Division system and method

Abstract: A system and method for digital division employing a composite of table lookup and iteration techniques. A stored logic table is used which generates a factor M which when multiplied against the divisor, provides a new divisor in a predetermined range close to unity in value. Both the divisor and the dividend are then multiplied by the factor M, the capacity of the table lookup determining the maximum difference of the new divisor from unity. The arrangement is such that, depending upon the difference between the new divisor and unity, a selected number of new partial quotient digits is directly determined from a selected number of digits in newly generated partial remainders. By generating quotient digits in successive groups, only a few iterations are needed to divide one long number by another. Successive division steps entail merely the generation of new partial products, and derivation of the difference of these partial products from the previous partial remainder. By arranging the significant portion of the new divisor to be a negative quantity in a preferred form of system, only adder circuits need by employed. A high speed, high capacity binary digital division system utilizing these techniques is further arranged to utilize carry-save adder circuits to utilize carry and sum quantities without introducing carry propagation delays, and otherwise minimize operating cycle time.

Time division multiplex data switch

Abstract: A time division multiplex data switch wherein any one of a plurality of input channels forming a plurality of input groups may be switched to any one of a plurality of output channels forming a plurality of output groups, which includes individually synchronized bit distributors associated with each input group, for distributing the bits to a plurality of single-bit stores, each associated with a channel, and a single-time division highway controlled by a dynamic memory.

Tandem office time division switching system

Abstract: A tandem office switching system is disclosed which will accommodate both digital and analog signals transmitted in single or multiplexed message form. A space division system switches analog signals received in serial single message form and a time division system switches digital signals received in multiplex message form. All signals received in the time division system are processed in accordance with timing derived from the incoming digital signals while signals transmitted from the time division system are processed in accordance with the tandem office timing. The system permits the switching of incoming analog signals to outgoing digital trunks and incoming digital signals to outgoing analog trunks through both space and time division systems.

Improvements in or relating to sealing strips

Abstract: 1,127,308. Moulding sealing strips. ST. ALBANS RUBBER CO. Ltd. 9 Feb., 1967 [16 Feb., 1966], No. 6787/66. Heading B5A. [Also in Division E1] A sealing strip with a hollow interior (3) is made by moulding the material in a split mould containing a plurality of inwardly directed axially spaced projections which support the core defining the hollow interior (3), the projections defining holes (4) in the wall of the strip. The strip is preferably made of a vulcanizable elastomer and comprises a core 2 of foam surrounded by two layers (1) of solid elastomer. A relatively non-extendable component such as yarn filament or wire may also be incorporated in, or on the boundary of the foam. It may be formed by introducing the precursor of the foam in a strip with a strip of solid elastomer attached to one or both sides, foaming and vulcanizing. The mould is preferably horizontal with the projections upstanding from the base, the holes (4) formed by these pins allowing expulsion of air during compression of the strip.

Time division self-correcting switching system

Abstract: A semielectronic line concentrator comprising electromechanical interconnection components and electronic control supervisory and control logic circuits. The concentrator adopts the principle of time division under control of a base frequency which is the highest frequency at which two successive operations on a plurality of stations may be performed. A second-order cycle whose frequency is a submultiple of the base frequency is used in conjunction with the base frequency. Furthermore, the system principle is arranged to be extended by the use of a third-ormore order cycle. There are control circuits responsive to these order cycles to correct automatically for errors in connections owing to noise or unexplained malfunctions.

Distance measuring device having a common optical system for the transmitted and received beams

Abstract: 1,030,290. Photo-electric distance measurement. AZA AB. Dec. 3, 1964 [Dec. 12, 1963], No. 49167/04. Heading H4D. [Also in Division G2] Apparatus for measuring distance by using the known velocity of light comprises a transmitter and a receiver having a common optical system which is divided between them by opaque partitions. As described, a housing 10 is split into two compartments 11, 12 by a partition 13 and has a recess 19 into which is fitted an optical system 20 comprising a pair of prisms 29, a concave reflector 23, and a spherical glass disc 30, the centre part 32 of whose inner convex surface 30 is aluminized to make it reflect. Opaque barriers 22, 25, provided with leaves 26, 33 to allow axial adjustment movements to be made, divide the optical system into two parts which communicate with the compartments 11, 12 through apertures 15, 39. A notch may be provided in disc 30 for receiving the barrier. Compartment 11 contains a light source 16 and a Kerr cell 18 and compartment 12 contains a photoelectric cell 43 and a movable glass plate 40, which is set at 45 degrees and may be moved to position 40 1 to enable sighting through an eyepiece 42. The transmitted light beam may be modulated at a suitable frequency by the Kerr cell and a phase comparison may be made with the received beam to determine distance. The prisms 29 may be moved forwards out of the way of the apertures 15, 39 so that light from the source 16 reaches the photo-cell 43 directly, when calibration may be effected.

Frame synchronization circuit

Abstract: The framing code of a time division multiplex digital data is compared cyclically with the local framing timing signals. When the comparison results in an out-of-frame condition, this condition is stored in a flip-flop and the results of the preceding j comparisons are stored in a j-stage shift register. A framing error signal is produced when the flip-flop and any k stages of the shift register simultaneously indicate an out-offrame condition. This error signal shifts the relative timing of the data and timing signals until an in-frame condition is produced by the comparison to inhibit the error signal.

Improvements relating to travel cases, trunks and the like

Abstract: 1,125,925. Suitcases &c. ANTLER Ltd. 27 June, 1967 [7 July, 1966], No. 30452/66. Heading B8P. [Also in Division E2] In a suitcase &c. of the type having metal reinforcing frames around the body and lid shells, at least one of the frames 2 is formed with a channel 5 having one wall 3 deeper than the other 6, and a double U spring clip is located in the channel, one portion 8 of the clip embracing the deeper wall 3 and having one or more barbs or detents 11 engaging the wall to hold the clip in place, and the outer wall of the second U-portion 7 has a tapped hole 13 receiving a screw 14 for fastening an internal fitting, e.g. a bracket 16, in place. The intermediate portion 12 of the bracket opposite the screw-hole has an opening to allow the end of the screw to contact directly upon the wall 6 of the channel whereby the U-portion 7 may be expanded within the channel to prevent longitudinal movement of the clip.

Improvements in electrical busway apparatus

Abstract: 1,103,307. Busbars. GENERAL ELECTRIC CO. 3 June, 1965, No. 23694/65. Heading H1A. [Also in Division H2] Housing 3 for electrical busways comprises top wall 4, support flanges 5 and 6, base flanges 11 and 12 and side walls 7 and 8 shaped to support the resilient insulating body 13 which in turn supports conductors 23, 24 and 25. A device 26 may be plugged in at any point, its contacts being pinched by the inwardlybent edges of the conductors. Adjacent sections of busway are electrically interconnected by means of lengths of tubular conductor (see Figs. 5 and 7, not shown), which fit into the ends of conductors 23, 24, 25 and which are slotted along the bottom to correspond with the slots in the bus conductors. That part of the connecting conductor not inserted is covered with adhering insulation. For added resilience, the ends to be inserted may be formed into prongs by having an additional slot along the top (Figs. 8, 9, not shown). Corresponding sections of the housing 3 are connected together at the same time by means of coupling plates 35 and 36, best seen in Figs. 1 and 6 (not shown). Clips 37, disengageable by tongues 37a, have projections to engage with slots in the base flanges and support flanges. The coupling plates are in position when a spring on the clip engages a hole in the plate and the adjacent busway sections are then pushed together.

Improvements relating to opening and mixing machines

Abstract: 1,131,097 Mixing fibrous materials FOSTER YATES & THOM Ltd 31 July, 1967 [26 Aug, 1966], No 38388/66 Heading B1C [Also in Division Dl] Apparatus for opening asbestos and mixing the fibres with other material or with different grades of asbestos comprises a rotatable container 1 with independently rotatable stirrers 22 The container is mounted on trunnions 5 and is rotated by a motor through a drive belt at the left hand side of the Figure, while the stirrers are mounted on a shaft 15 passing through the trunnions and rotated in the same or opposite direction by a motor through a drive belt 14 Each stirrer comprises two discs arranged back to back, and has three vanes 24 on each side, and openings (25, Fig 4, not shown) The discs are eccentrically mounted on the shaft

On the nature of conjugate vortex flows

Abstract: Conjugate solutions of the equation of swirling cylindrical flow are considered in the case where the ‘primary’ flow has constant axial velocity. Numerical solutions are exhibited, which suggest a division of primary flows into four classes, and some conditions governing membership of these classes are derived. Finally, the case when the governing equation is slightly non-linear is considered.

Improvements in or relating to pressure devices

Abstract: 1,134,101. Gas filter. BABCOCK & WILCOX Ltd. 30 Nov., 1965 [1 Sept., 1964], No. 35824/64. Heading BIT. [Also in Division GI] Pressure responsive apparatus for measuring the gas pressure of a gas/solid suspension, for example a heat transfer liquid in a nuclear reaction plant, comprises a cylindrical vessel 1 with inlet 4 and outlet 5 connected to a pressure sensitive element, and a transverse filter 11 which divides the vessel into inlet and outlet chambers. The inlet 4 may be connected via a piezometer ring 8 with apertured channel 9 encircling conduit 6 passing a gas/solid solution. The filter rejects particles exceeding a certain size e.g. 5 microns, and may comprise three discs connected by impervious sections and coplanar.

Temperature indicating device

Abstract: 1,134,027. Optical apparatus. W. DABISCH. May 17, 1967, No.58798/67. Divided out of 1,134,026. Heading G2J. [Also in Division G1] The present Specification is divided from Specification 1,134,026 and is concerned with the construction and composition of the Christiansen optical filters as disclosed in that Specification.

Improvements in or relating to lubrication of turbo-units

Abstract: 1,102,937. Bearings; lubricating. WESTLAND AIRCRAFT Ltd. 17 Aug., 1966 [18 Aug., 1965], No. 35517/66. Heading F2A. [Also in Division F1] Ball or roller bearings of a turbo-unit are lubricated by means of an oil-mist circulated therethrough by a rotary air-pump, the oil-mist being produced by passage of air over oil deposited on the shaft of the unit. The oilentraining air is returned to the air-pump after having passed through the bearings. In an embodiment, a shaft 4 has two rotary air-pumps 11 mounted thereon, is supplied with lubricant by means of two wicks 10 which lead to an oilsump 9, and is supported by ball-bearings 5 mounted in a carrier 6. The latter is provided with radial fins and is received in a sleeve 7, the radial fins dividing the cylindrical space between the carrier 6 and the sleeve 7 into an even number of longitudinal passages divided into two interdigitated groups allocated respectively to the circulation of air carrying lubricating mist and to cooling air. The oil-mist is passed through longitudinal passages 13, through the bearings 5 and is returned to the passages 13 via circular grooves 16 in endplates 14, 15 and ports 17. Cooling-air is forced through ports 23 into longitudinal passages 24 by a fan 22 mounted on the shaft 4 and enters through ports 25 into an annular space formed between the end-plate 15 and a restrictor-plate 26. The cooling air then escapes through an annular gap 27 formed by the plate 26 and a collar 21 of the shaft 4, and, in escaping causes a back-pressure which is sufficient to prevent leakage of oil through a labyrinth seal 19 provided between the collar 21 and the end-plate 15. In modifications, the wicks 10 may be replaced by small-bore pipes, the circulating air being passed over the ends thereof and a breather arrangement may be provided.