Time and Amplitude Statistics for Electromagnetic Noise in Mines

The time and amplitude statistics illustrated are important and useful in describing the time-dependent, measured electromagnetic (EM) noise in mines. They are 1) Allan variance analyses (AVA), 2) interpulse spacing distributions (ISD), 3) pulse duration distributions (PDD), 4) average crossing rates (ACR), and 5) amplitude probability distributions (APD). These statistics are illustrated using a rather large store of raw analog data measured in operatioal mines through computer software techniques. The curves generated for the figures characterize the noise environment in the mines from which the corresponding data were taken, and should aid in the design of reliable communication systems for such mines.