common-mode interference

Geophysics ◽  
1982 ◽  
Vol 47 (12) ◽  
pp. 1672-1680 ◽  
Author(s):  
Miles A. Smither ◽  
Arnold Pater

In spite of the prevalence of high common mode rejection ratio (CMRR) input amplifiers, notch filters are routinely used in seismic recording operations to reduce common mode induced interference. An electrical model of the recording environment which predicts the degradation in system CMRR caused by cable imperfections such as imbalance and leakage is described in this paper. System CMRRs as low as 20 dB can be caused by poor quality cables. A new method of controlling common mode interference has been developed which has none of the disadvantages of notch filters. The method minimizes the correlation between the common mode and differential mode signals at the recording instrument. This process has no effect on the desired seismic signals, has minimal effect on the system noise, and typically results in a system CMRR in excess of 100 dB.


2020 ◽  
Vol 330 ◽  
pp. 108467 ◽  
Author(s):  
Todd J. Levy ◽  
Umair Ahmed ◽  
Tea Tsaava ◽  
Yao-Chuan Chang ◽  
Peter J. Lorraine ◽  
...  

Electronics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 862
Author(s):  
Fengchuan Wu ◽  
Yuejun Zheng ◽  
Yunqi Fu

A magnetic-free multifunction nonreciprocal device based on switched delay lines (SDLs) has been proposed in this paper. It is constructed with two double balanced gyrators (DBGs) and four baluns, each pair of differential ports of the balun connect the ports at the same orientation of the two DBGs, respectively. Due to the asymmetry of the clock control signals acting on the switches, the time reversal symmetry of the transmission line between the Gilbert quad-switch-sets (GQSS) can be broken to achieve non-reciprocity. It can be used as a circulator, gyrator, or isolator by setting different control signals. The device has infinite working bandwidth in theory based on the SDLs. Common mode interference can be better suppressed by using differential transmission structures. Moreover, power capacity can be improved compared to the previous work. Then, experiments have been done to verify the device as a circulator. Broadband property and the anti-interference property have been verified.


2013 ◽  
Vol 340 ◽  
pp. 418-421
Author(s):  
Xiao Ming Chang ◽  
Chun Geng Gao

To analyze the causes of common-mode interference from the definition of common-mode voltage, and the combination of graphics using mathematical formula image illustrates the size of common-mode voltage. At the same time, to analyze the method and defects of common-mode interference in the traditional two-line balanced communication line. On this basis, a cost-effective solution circuit is proposed. The results prove that the circuit has the advantages of low cost, simple structure, convenient features.


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