Analysis and correction of noise on electronic circuits in an accelerator environment

The generation and propagation of noise in the electrical system in an accelerator system are examined. Some approaches to reducing or eliminating the effect of noise on the electronic circuits are discussed. Recommendations on design, wiring, and connections are made. The use of separate ground leads for digital and analog signals to eliminate the undesired coupling of signals via common ground leads is also covered. In mixed mode printed-circuit boards, the importance of physical separations between analog and digital circuits is emphasized. In general, for analog signal transmission, use of a differential mode to reduce common-mode noise and shielded twisted pairs to minimize noise pick-up is recommended. Optical coupling can be used to reduce noise transfer into electronic circuits. The ground conductor should be used only for grounding purposes. In three-phase systems care must be taken to reduce the amount of phase imbalance due to improper loading of different phases. A 6- or 12-pulse supply fed from a balanced three-phase system introduces less current harmonic back into the line than when it is fed from an imbalanced system