| Summary: | 碩士 === 南臺科技大學 === 電子工程系 === 107 === Power-Line Communication (PLC) technology has been applied to remote control and signal sensing since the 20th century. In 2001, PLC was used to realize broadband communication in power line networks. This technology enables data being sent over existing power cables and currently most companies offer the last mile solutions with an AC-based PLC scheme. The applications of DC-based PLC are relatively less. This thesis designs and implements a power line communication transceiver on a DC 12 to 24 volt power line.
The proposed DC-based PLC transceiver is modularly designed and consists of signal processing and control (SPC) module, analog front-end (AFE) module and power supply (PS) module. The SPC module uses the STM32F405 microcontroller with digital signal processing (DSP) function as control and computation core to implement the orthogonal frequency division multiplexing (OFDM) modulation technology. The interpolation algorithm and channel estimation are carried out to fix the phase distortion of received data. In this module, the input and output signals are processed with ADC and DAC, receptively. In the AFE module, OFDM signal is preprocessed by a fourth-order band-pass filter. And the half-bridge current driver provides the processed signal with sufficient current for being coupled into the DC power line. When the AFE module receives the signal, the fourth-order band-pass filter is used to filter out the noise and DC components from power line. The gain control and voltage clamping of the signal are fulfilled by the two inverting amplifiers formed with LT1816 and TL072 and then the processed signals are demodulated. The PS module uses a RC-Pi type power filter to filter out the signals from the DC power line, and then utilizes LM317A for voltage stabilization to obtain a DC power to supply the SPC and AFE modules. In this thesis, we integrate the aforementioned modules and program firmware to realize a set of transceivers for DC 12 to 24 volt power line communication. The transmission signals are in the frequency band of 42 to 58 kHz and the data rate achieves 24 kbps. The signal transmission performance of the implemented DC-based PLC transceiver is verified on a DC 12 to 24 volt power line through texts and images being sent and received successfully.
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