Digital transmission system

A digital transmission system having a transmitting apparatus that transmits digital data signals and a receiving apparatus that receives the digital data signals transmitted over a transmission path, compares them with a predetermined threshold value, and performs decision reproduction, wherein

• the receiving apparatus comprises:
• k number (i.e., k×n) of decision circuit sets each having different threshold values, with one set formed by a plurality (n number) of decision circuits having the same threshold value;
• distribution circuits that distribute reception signals to the decision circuits;
• a selection circuit that selects and outputs one decision result from the decision circuits;
• and
• a control circuit that controls the selection circuit such that the input of the decision results is received from each decision circuit, a set in which the decision results of n number of decision circuits are the same is selected from all sets, and the decision result of one decision circuit from that one set is selected.

A digital transmission system having a transmitting apparatus that transmits digital data optical signals and a receiving apparatus that receives the digital data optical signals transmitted over an optical transmission path, converts the digital data optical signals into electrical signals, compares the electrical signals with a predetermined threshold value, and performs decision reproduction, wherein

• the receiving apparatus comprises:
• k number (i.e., k×n) of decision circuit sets each having different threshold values, with one set formed by a plurality (n number) of decision circuits having the same threshold value;
• distribution circuits that distribute the electrical signals to the decision circuits;
• a selection circuit that selects and outputs one decision result from the decision circuits;
• and
• a control circuit that controls the selection circuit such that the input of the decision results is received from each decision circuit, a set in which the decision results of n number of decision circuits are the same is selected from all sets, and the decision result of one decision circuit from that one set is selected.

A digital transmission system having a transmitting apparatus that transmits digital data optical signals and a receiving apparatus that receives the digital data optical signals transmitted over an optical transmission path, converts the digital data optical signals into electrical signals, compares the electrical signals with a predetermined threshold value, and performs decision reproduction, wherein

• the receiving apparatus comprises:
• k number (i.e., k×n) of decision circuit sets each having different threshold values, with one set formed by a plurality (n number) of decision circuits having the same threshold value;
• an optical distribution circuit that distributes the digital data optical signals to n series;
• n series of photo detectors that receive the optical signals distributed to the n series;
• optical amplifiers that amplify optical signals at at least one of the optical distribution circuits and the photo detectors that are upstream of the optical amplifiers;
• n series of distribution circuits that distribute the electrical signals output from the n series of photo detectors to the k sets of decision circuits that each have a different threshold value;
• a selection circuit that selects and outputs one decision result from the decision circuits;
• and
• a control circuit that controls the selection circuit such that the input of the decision results is received from each decision circuit, a set in which the decision results of n number of decision circuits are the same is selected from all sets, and the decision result of one decision circuit from that one set is selected.