Dual-channel Metal Debris Signal Differential Detection Based on Frequency Division Multiplexing

Inductance oil detection sensors face the challenge of not being able to simultaneously increase both detection sensitivity and detection throughput. In this paper, based on the inductive detection method, a bridge detection circuit is used to improve the detection sensitivity. The combination of frequency division multiplexing technology and oil abrasive grain detection can achieve dual-channel oil pollutant crossover frequency simultaneous differentiated detection, which improves the throughput of oil abrasive grain detection. A dual-channel inductive oil detection chip is designed, and the excitation frequency, component parameters and coil size parameters of the AC inductive bridge are optimized through simulation. The dual-channel detection signals are modulated by amplitude modulation so that the dual-channel metal abrasive inductance detection signals are carried in a synthetic modulated signal, and there is no need to increase the data acquisition equipment. Design of signal processing and modulation circuit system, the choice of conventional amplitude modulation analog modulation method, combined with the Hilbert transform and the absolute value of the function composed of the envelope detector digital demodulation method, to achieve the simultaneous differentiated detection of dual-channel. Experimental results show that the dual-channel frequency division multiplexing system can complete the simultaneous detection of two-channel oil metal abrasive grains and the acquisition of synthetic modulated signals, and can be quickly analyzed by the digital demodulation model of the synthetic modulated signals of oil metal abrasive grain information.