航空电缆故障检测设备的ADC增频方法

Method for Increasing ADC Sampling Frequency of Aviation Cable Fault Detection Equipment

航空电缆用于连接电源设备和其他系统设备,以传输电能和信号,其性能直接影响飞机的运行安全,因此必须对航空电缆的故障进行严格的检测和排除。时域反射技术(Time Domain Reflectometry, TDR)是目前最为成熟的电缆故障检测方法,该技术根据反射脉冲与发射脉冲的时间间隔和相位关系来判断故障位置和类型。基于TDR技术的电缆故障检测设备通常使用ADC(Analog-to-Digital Converter)模块对检测信号进行采样,采样频率在很大程度上决定了故障检测精度。目前主要通过使用高精度的ADC采样模块或构建延时线来获得更高的采样精度,但是存在增加系统成本和复杂度的问题。针对上述问题,设计了一种ADC等效采样法,该方法通过对参考时钟延时得到延时时钟,依次以各延时时钟作为采样时钟对检测脉冲进行采样,采样结束后,依照采样顺序对采样数据进行排序并重构检测波形,从而在使用频率较低的ADC采样模块的情况下,获得更高的采样精度,极大地提高了基于TDR技术的电缆故障检测方法的精度。

Aviation cables are used to connect power supply equipment and other system equipments to transmit electrical energy and signals.Their performance directly affects the safety of the aircraft.Therefore,aviation cable faults must be strictly tested and eliminated.Time Domain Reflectometry(TDR)is currently the most mature cable fault detection method.This technology determines the fault location and type based on the time interval and phase relationship between the reflected pulse and the transmitted pulse.Cable fault detection equipment based on TDR usually uses the ADC module to sample the detection signal,and the sampling frequency largely determines the fault detection accuracy.At present,high-precision ADC sampling modules or Delay Line are mainly used to achieve higher sampling accuracy,but there are problems of increasing system cost and complexity.In view of the above problems,an ADC equivalent sampling method is designed.This method obtains the delayed clock by delaying the reference clock,and sequentially uses the delayed clocks as the sampling clock to sample the detection pulse.After sampling,the sampled data is sorted according to the sampling order and the detected waveform is reconstructed.Therefore,in the case of using a lower frequency ADC sampling module,a higher sampling accuracy is achieved,and the accuracy of the cable fault detection method based on the TDR technology is greatly improved.