DATA UNDER VOICE COMMUNICATIONS SYSTEM

摘要

A communications system capable of simultaneously transmitting voice and data information. The spectral energy of the data signal is smeared by spreading it in a spectrum with energy packed in the lower frequency range under the conventional voice signal frequency in a manner which complements the standard C-message weighting curve. The use of the spread spectrum technique also eliminates thumping at the data rate since the harmonics that produce thumping are also spread throughout the bandwidth.