DISTRIBUTION LINE CARRIER RECEIVER

• Main Author: MITANI SHIGEO
• Format: Patent
• Language: English
• Published: 30.04.1993
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION

PURPOSE:To eliminate a data error against external interference due to a load of distribution line and its transmission characteristic by detecting a zero cross point of a power supply frequency component, calculating the neighbouring point of a maximum value and a minimum value with a timer and increasing a gain of an amplifier for a period attenuation period. CONSTITUTION:A reception signal inputted to a distribution line 15 is detected by a CT 1 and inputted to an amplifier 9 via a resistor 2 and a notch filter 4. On the other hand, a reception signal detected by the CT 1 is amplified by an amplifier 3 and a zero cross comparator 5 detects a zero cross point to start a timer 10. The timer 10 is started at a time T2 backward from 1/4 of a power supply period from a zero cross point and a timer 11 is started at a time T1 forward from 1/4 of the power supply period from the zero cross point, a switch 6 selects a resistor 8 and a gain of the amplifier 9 is set to a gain at which no reception signal is attenuated. The signal corrected from the amplifier 9 is outputted as demodulation data via a BPF 12, an A/D converter 13 and a correlation device 14.