| 摘要 |
PROBLEM TO BE SOLVED: To provide a noise filter capable of flexibly corresponding to a resonance frequency and effectively reducing a noise in the resonance frequency, even when a resonance frequency is changed, the resonance frequency being caused by a floating capacitance due to a differential transmission cable and a common mode inductance of a common mode choke coil.SOLUTION: A noise filter 1 includes: a common mode choke coil 10 having a first coil 101 and a second coil 102; a first LC series resistance circuit 21 connected between one end of the first coil 101 and the ground; and a second LC series resistance circuit 22 connected between one end of the second coil 102 and the ground. Constants of coils 213, 224 and capacitors 211, 222 configuring the first LC series resonance circuit 21 and the second LC series resonance circuit 22 are set according to the resonance frequency of the resonance caused by a common mode inductance of the common mode choke coil 10 and a floating capacitance 51 formed between a differential transmission cable 50 and the ground.SELECTED DRAWING: Figure 1 |
