Noise Susceptibility in Analog and Digital Signal Processing Systems

A demonstrable cause-and-effect relationship between a popular and widely employed equipment design practice and electrical noise problems in audio systems of all kinds is examined. A means of identifying equipment that may exhibit noise problems due to this design practice is outlined. The relationship between the physical construction of shielded twisted-pair cable and induced noise in a signal circuit due to cable shield current is explored. Established rules for equipment installation are reexamined. It is shown that noise problems due to this design practice could be eliminated at the manufacturing level at almost negligible net cost.