DISTRIBUTION LINE CARRYING RECEIVER

• Main Author: MITANI SHIGEO
• Format: Patent
• Language: English
• Published: 18.10.1994
• Edition: 5
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION

PURPOSE:To prevent a distribution line carrying system from being stopped by judging excessive noise of a single frequency in the vicinity of a signal frequency which occurs in a distribution system as a controller abnormality. CONSTITUTION:The output of a current transformer (CT) 2 of a signal which is injected into distribution lines 1-a to 1-c and for which a digital modulation is performed is inputted in an analog BPF 3, the output is transmitted via an amplifier 4 and an A/D converter 5, the digital data for which an A/D conversion is performed is inputted in a digital filter 6, the output is inputted in a carrier detection circuit 7, the output of the carrier detection circuit 7 is inputted in an FSK demodulation circuit 8, the data for which the FSK demodulation is performed is inputted in a distribution line carrier controller 9 and a memory 19 storing data, a comparator 1 (20) comparing data with the data one time before, a counter 21 counting the result of the comparator 1 (20), a comparator 2 (16) comparing the output of the counter 21 with the output of a setting circuit 17 which is set to a certain constant and the output of the comparator 2 (16) are inputted in the memory 19 and a gate circuit 10 where carrier detection signals are made off for fixed time, and the output of the gate circuit 10 is inputted in a main controller 9.