Power line channel transmission characteristic measurement method and system based on orthogonal spread spectrum sequence

Abstract

The invention discloses a power line channel transmission characteristic measurement method based on an orthogonal spread spectrum sequence, and the method comprises the following steps that a transmitting end control unit generates a test vector V of a frequency point f and an output amplitude A according to a measurement range and a precision requirement; the spread spectrum modulation unit sequentially sets the frequency and amplitude of the modulation signal at a certain time interval Ts according to the test vector V, and performs spread spectrum sequence modulation to obtain a first output signal; the sending end coupling unit injects the first output signal of the spread spectrum modulation unit into the input end of the tested channel; the receiving end coupling unit receives the measurement signal from the tested channel and outputs a second output signal; the receiving end frequency conversion processing unit performs frequency conversion processing on the second output signal; the power correlation calculation unit performs sliding correlation integral operation on the variable frequency output signals and sends effective calculation results to the receiving end controlunit; and the receiving end control unit is used for counting and smoothing the effective calculation result and then calibrating the measurement result.

Description

technical field [0001] The invention relates to the technical field of power line carrier communication, in particular to a method and system for measuring power line channel transmission characteristics based on orthogonal spread spectrum sequences. Background technique [0002] For the low-voltage distribution network, the power line carrier communication generally has the following characteristics: 1) The time-varying nature of the communication channel. Due to the characteristics of the low-voltage distribution network such as very complex load conditions, large load variations, and many types of noise, each If the node impedance does not match, the signal is prone to reflection, standing wave, resonance and other phenomena, which makes the attenuation of the signal extremely complicated, resulting in a strong frequency selectivity of the power carrier communication channel. 2) Noise interference is strong and signal attenuation is large. Generally speaking, there are ma...

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Problems solved by technology

However, signal synchronization requires high signal-to-noise ratio of the received signal, and in actual power line channel measurement, channel measurement in a high-noise environment and low signal-to-noise ratio is often required, so the method of this patent has great limitations

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