The Design And Realization On Low-coltage Power Line Data Transmit System

It had very high economy, universality and practicability that using power line as communications medium. The temporal variation and powerful interference of low-voltage power line channel, which had high bit error rate and low reliability when data were transmitted compared with the traditional line channel. So increasing transmissive reliability was important meaning for low-voltage power line carrier communications when the data was transmitted based on low-voltage power line channel.The idiographic channel's error rate was jointly determined by low-voltage power line channel-specific features and different modulation and encoding and decoding arithmetic. Spread spectrum communication could work in low SNR, The error control coding could increasing transmissive reliability. Low-voltage power line channel had the temporal variation and powerful interference. So the article adopted the unite mode of spread-spectrum communication and error control coding, the anti-interference ability of the system was advanced. It was insolubility that the impedance mismatch caused the signal drops by spread spectrum communication.In order to solved this problem, The complementary output circuit was adopted in the transmitter output stage when hardware circuit was designed, which improved the system with load capacity. MATLAB was used analysis and comparison for the system, which was based on that a low bit error rate of convolution encoding and decoding and direct sequence spread spectrum communication system was designed.The overall program was designed based on simulation analyse. The design used a upper cost and capability chip PL3106 that was a spread spectrum communication module, and it was completed that a low-voltage power line data transmission system hardware and software design and system debugging.The results showed that the system had improved transmission system reliability, it could work in low SNR, which had a lower error rate. This system could be used in less demanding real-time, high reliability requirements of the low-power line transmission system.