The whole system of the filter electric connector is composed of a whole system structure of the 3.1 filtering electric connector, and the whole system structure of the filter electric connector is mainly pided into three parts, namely the signal source, the connection interface and the receiving circuit. The filter is the window of the signal input and output of the whole device, and how it will directly determine the electromagnetic compatibility of the whole system. The filter used in this paper is a passive filter, the main reason is to choose the passive filter, the main consideration is to optimize the design of passive filter to meet the overall economic and practical filter electrical connector.

The passive filter is a frequency selective network composed of R-C, L-C and other passive devices, it only allows the frequency band signal given by the other band signal will be "banned". The range of passive filter includes large, including to suppress the low frequency oscillation of power amplifier for decoupling filter, smoothing filter for the purpose in the rectifier circuit, filter ripple for low-pass filter to filter out high frequency interference power network in AC power input, etc..

Among the passive filters, the bypass filter is one of the filters which can be used to filter the interference signals in the power network. The typical application of bypass filter is mainly manifested in the following two aspects: first, to retain and filter the high frequency signal in high-frequency circuits; secondly, in the circuit of AC and DC superimposed AC component in signal filtering and keep DC component.

As a low pass filter weak signal of low voltage circuit, under normal circumstances, the filter can meet the standard to select the frequency band, there is no strict or too high performance requirements, and the relevant requirements of the current impact, capacitor voltage is not very high. For example, the smoothing filter used to filter out the power ripple can be regarded as a low-pass filter which can be filtered in essence.

To examine the bypass filter and decoupling filter from the filtering purposes, they are essentially identical, just play ways there are certain differences in the specific role of the bypass filter: filter from the perspective of input filter to complete the mission, the filter object is the electromagnetic interference of the input signal is output from the filter; decoupling point complete the filtering mission, the filtering object is the output signal of the electromagnetic interference. Both can provide an effective filtering function, through the above analysis we can also know that, as long as we follow the above principles, we can use the filter to filter out more unnecessary electromagnetic interference.