Noise-loading test of a complete frequency-division multiplex voice point-to-point communication system
Leang P. Yeh · Transactions of the American Institute of Electrical Engineers Part I Communication and Electronics · 1962
THE QUALITY or noise performance of a complete multiplex voice point-to-point communication system is usually specified, following telephone transmission practice, by the allowable noise power per voice channel not to exceed certain percentile of time at a point of zero relative level (0 dbm [decibels referred to 1 milliwatt] at the sending toll switchboard).