Abstract: A decision feed back equalizer provides two feedback routines for one symbol-preceding decided data. The signal space is separated into decidable areas and uncertainty areas. Within each of decidable area the distance between any point and the signal point is small. Within each uncertainty area the distance between any point and the signal point is large. If the symbol-preceding equalized signal is in a decidable area, the piece of decided data is fed back, as it is presumed to be correct. If the symbol-preceding equalized signal exists in an uncertainty area, the piece of decided data is not fed back, as it is presumed to be in error. Here the one piece data is selected from all the predicted symbol-preceding decided data so that the instant equalized data is now in the decidable area. This piece of decided data is now fed back.

Abstract: A decision feed back equalizer is proposed, in which two feed back routins are provided for one symbol-preceding decided data. The signal space is separated into decidable areas and uncertainty areas in the present invention. Each of decidable areas is an area where a distance between any point in the decidable area and the signal point is small. Each uncertainty areas is an area where a distance between any point in the uncertainty area and the signal point is large. In a case where the one symbol-preceding equalized signal exists in a decidable area, since the one symbol-preceding decided data is presumed to be correct, the decided data is fed back.

Abstract: A synchronizing system in a digital communication line comprises a plurality of local switches for storing at least one digital line and monitoring a first piece of busy information when a clock source is already present, the local switches, if a first new clock source occurs while the first busy information is indicating no busy state, being capable of transmitting a master right request to turn the busy information to the busy state and to specify the first new clock source as a master clock and, on receiving a master right specification with respect to the master right request, being capable of outputting the first new clock source as the master clock; and a master switch connected to the plurality local switches in a star manner, by a link transmission line for transmitting control information including the master clock, master right request and master right specification, for monitoring a second piece of busy information indicating a busy state, the master switch, if a second new clock source occurs whil

Abstract: The polymer or a copolymer of trioxane copolymer is manufactured by adding 0.001 to 2.0 wt. % of a stereo-hindering phenol to the monomer mixture in advance to the polymerization step and polymerizing trioxane and an optional co-monomer in the presence of a cationic, active catalyst and said phenol.

Abstract: A trioxane copolymer is manufactured by adding to trioxane and a co-monomer, 0.0001 to 2.0 percent by weight, based on the total weight of the monomers, of one or more sterically hindered phenols, then co-polymerizing the resultant mixture in the presence of a cation-active catalyst, and then treating the resultant copolymer by heating it at a temperature which is higher than the melting point of the copolymer to melt the copolymer and decompose and remove unstable parts of the copolymer.