Power supply self-synchronizing phase inversion modulator-demodulator for power line communication

Abstract

The invention discloses a power supply self-synchronizing phase inversion modulator-demodulator for power line communication, which adopts asymmetrical phase inversion modulation as a transmission signal, and utilizes the characteristic that a receiving terminal and a transmitting terminal have the same supply frequency, a typical phase-locked loop frequency synthesizer is firstly adopted to realize a signal generator which is strictly synchronous with the supply frequency, the synchronous signal generator is then utilized to replace a conventional crystal oscillator, accordingly, the receiving-transmitting frequency difference is thoroughly eliminated, the required steps of synchronization of carrier wave, sampling and clock for a power line digital communication receiver are completely omitted, so the self-synchronizing of a phase inversion modulation digital receiver demodulator for power line communication is realized.

Description

technical field [0001] The invention belongs to the technical field of digital communication, and relates to a power line carrier data communication system, in particular to a method for transmitting and receiving synchronization of a low-voltage power line carrier modem, and more specifically, to a power supply self-synchronizing reverse phase modem for power line communication. Background technique [0002] It is well known that synchronization is the basis of digital communication. In a wireless communication system, due to factors such as Doppler frequency shift and oscillator stability, the transceiver frequency deviation and phase inconsistency, so the receiving end must first solve the carrier synchronization, that is, obtain or restore the carrier with the same frequency and phase as the sending end frequency. On this basis, a sampling pulse with a proportional relationship with the carrier frequency or symbol rate is further obtained, that is, sampling (clock) sync...

AI Technical Summary

Problems solved by technology

[0004] The traditional PLC system mainly adopts classic frequency shift keying (FSK) modulation or phase shift keying (PSK) modulation, and the demodulator first needs to recover the carrier wave when using coherent demodulation, and the structure is relatively complicated; recently, in order to improve the anti-interference ability, Modern communication technologies such as direct spread spectrum and orthogonal frequency division multiplexing (OFDM) are also used, but the bottom layer is still the basic BPSK (binary) or QPSK (quaternary) In terms of interference performance, it is still inevitable to lose sight of the other, and it is at the cost of greatly increasing the complexity of the system

Therefore, there is still a gap in existing technologies and products in meeting market demands

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