Abstract: An encoding (or decoding) method, by which raw data of 1 line is converted into, for example, modified Huffman (MH) code (or MH code is converted into raw data) by obtaining a cumulative run-length code every transition point, at which there occurs a transition or change between a run of white pixels to another contiguous run of black pixels, from the beginning of the line and then converting the cumulative run-length code to the MH code (or converting the MH code to the cumulative run-length code). The cumulative run-length code is defined by both of data, which indicates that a pixel of a run just prior to the transition point is black or white, and data representing a cumulative run-length of the run up to the pixel thereof just prior to the transition point. Thus, an encoding or decoding processing can be performed at a high speed.

Abstract: A Viterbi decoding method, in which consecutive input data bits Q.sub.6n .about.Q.sub.1n are first converted into consecutive code bits Q.sub.6n .about.Q.sub.3n Y.sub.2n Y.sub.1n Y.sub.0n at a time instant n by use of a Trellis encoder. Then, a branch metric, which is a minimum Euclidean distance between a reception signal point and each of signal points (namely, Trellis codes Q.sub.6 .about.Q.sub.3 Y.sub.2 Y.sub.1 Y.sub.0) in a signal space diagram, corresponding to each of eight states 0 to 7 and a corresponding signal point are obtained. Further, a sum of the branch metric corresponding to each state and a corresponding path metric at a time instant (n-1), which is a sum of corresponding branch metrics since a time instant 1 to the time instant (n-1) is calculated. Then, the path metric corresponding to each state is updated by replacing it with the calculated sum of the corresponding branch metric and the corresponding path metric obtained at the time instant (n-1).

Abstract: A process for producing polyester fibers having excellent tensile properties, particularly suitable as reinforcement material for tires, belts, etc., involves melt-spinning an ethylene terephthalate polyester to form highly oriented low crystalline polyester filaments which, at the state of being taken-up and prior to being drawn, having birefringence (.DELTA.n) and specific gravity (SG) within the below indicated ranges (a) and (b), and then, without winding-up, subjecting the said filaments immediately to drawing and heat treatment between the first godet rolls and second godet rolls under a draw ratio (DR) defined by the following formulas:.DELTA.n.gtoreq.5SG-6.64 (a).DELTA.n.gtoreq.0.100 (b)2.0.gtoreq.DR>1.

Abstract: Process for producing polyester fibers of high tenacity and high modulus, by melt-spinning a polyester having an intrinsic viscosity of not lower than 0.3, to obtain extruded filaments of low orientation having a birefringence not higher than 10.0.times.10.sup.-3, post-polymerizing the filaments in a heating medium, and subjecting the filaments to multi-stage drawing in at least two stages.

Abstract: A polyamide fiber excellent in strength, which comprises at least one of polycapramide, polyhexamethylene adipamide and polytetramethylene adipamide in an amount of not less than 60% by weight on the basis of the polyamide fiber and which is characterized by having a relative viscosity of not less than 2.3 and less than 3.5 (measured on a 96% by weight sulfuric acid solution having a polyamide concentration of 10 mg/ml at 20.degree. C.), an index of birefringence (.DELTA.n) (measured after 24 hours under the conditions of 30.degree. C. and 80% relative humidity) of not less than 55.times.10.sup.-3 and a tenacity of not less than 12.0 g/d. The method of preparing the noted polyamide fibers includes spinning of the polyamide to produce filaments, cooling the filaments, taking up the filaments to make an index of birefringence of 13.times.10.sup.-3 or less and drawing the filaments so taken up.

Abstract: Polyester fibers having both a high strength and a high modulus prepared from ethylene terephthalate polyester, and having an intrinsic viscosity of not less than 1.0 and an initial tensile modulus is not less than 130 g/d, said intrinsic viscosity being determined in a mixed solvent of p-chlorophenol and tetrachloro ethane (3:1) at 30.degree. C. Processes for producing the fibers are also disclosed.

Abstract: A polyamide fiber excellent in strength, which comprises at least one of polycapramide, polyhexamethylene adipamide and polytetramethylene adipamide in an amount of not less than 60% by weight on the basis of the polyamide fiber and which is characterized by having a relative viscosity of not less than 2.3 and less than 3.5 (measured on a 96% by weight sulfuric acid solution having a polyamide concentration of 10 mg/ml at 20.degree. C.), an index of birefringence (.DELTA.n) (measured after 24 hours under the conditions of 30.degree. C. and 80% relative humidity) of not less than 55.times.10.sup.-3 and a tenacity of not less than 12.0 g/d, the index of birefringence in section satisfying the following relationship:.DELTA.n.sub.A -.DELTA.n.sub.B .gtoreq.0(wherein .DELTA.n.sub.A is the index of birefringence of fiber at the position of r/R=0.9, .DELTA.n.sub.B is the index of birefringence of fiber at the position of r/R=0.

Abstract: A process for the manufacture of polyamide fibers including melt spinning a polyamide having a relative viscosity of not less than 3.50 under conditions satisfying the following relationships:Q/D.sup.3 .ltoreq.982 g/sec.cm.sup.3D.sup.2.Vw/Q.ltoreq.12.8 cm.sup.3 /gT.sub.20 .gtoreq.100.degree. C..DELTA.n of unstretched filaments.ltoreq.0.017The resultant filaments are then subjected to cooling, stretching and heat treatment resulting in fibers with a break strength of not less than 11.0 g/d, a break strength.times.(break elongation(%))1/2 of not less than 46.0 and a monofilament denier of not more than 60 d.

Abstract: A polyamide fiber excellent in strength, which is characterized by being made of a polyamide having a relative viscosity of not less than 3.5 (measured on a 96% by weight sulfuric acid solution having a polyamide concentration of 10 mg/ml at 20.degree. C.), showing an index of birefringence (.DELTA.n) of not less than 50.times.10.sup.-3 and having the following relationship between the break strength and the break elongation:Break strength (g/d).times.(Break elongation (%)).sup.1/2 .gtoreq.46.0, the index of birefringence in the section of fiber satisfying the following relationship:.DELTA.n.sub.A -.DELTA.n.sub.B .gtoreq.0.5.times.10.sup.-3(wherein .DELTA.n.sub.A is the index of birefringence of fiber at the position of r/R=0.9, .DELTA.n.sub.B is the index of birefringence of fiber at the position of r/R=0.0, R is the radius of the section of fiber and r is the distance from the central axis of the section of fiber).

Abstract: A polyamide fiber excellent in strength, which is characterized by having a relative viscosity of not less than 2.3 (measured on a 96% by weight sulfuric acid solution having a polyamide concentration of 10 mg/ml at 20.degree. C.), having an index of birefringence in section which satisfies the following relationship:.DELTA.n.sub.A -.DELTA.n.sub.B <0(wherein .DELTA.n.sub.A is the index of birefringence of fiber at the position of r/R=0.9, .DELTA.n.sub.B is the index of birefringence of fiber at the position of r/R=0.0., R is the radius of the fiber section and r is the distance from the central axis of the fiber section), and showing the following physical constants:Index of birefringence of fiber (.DELTA.n) (measured after 24 hours under the conditions of 30.degree. C. and 80% relative humidity) .gtoreq.50.times.10.sup.-3 ;Break strength .gtoreq.11 g/d;Fiber long period spacing value at length by small angle X-ray diffraction .gtoreq.100 .ANG.;Specific gravity .gtoreq.1.140;Dry heat shrinkage .ltoreq.15%.