Modem HF para voz digital interactiva: Rendimiento en enlace real

Abstract

The HF band data link has been traditionally desired by many large range transmission systems although it is associated to unfavorable performances as low transmission rate and large delay. Although transmission rates are usually high enough to transmit digital voice, delay, usually over some second, has been the main handicap to let the systems provide interactive digital voice links. Indeed, there is no unclassified equipment with this capability. The main achievement of this work is to provide digital voice transmission with very low latency, around 150 msec.(modem + vocodec), providing a full interactive digital voice link. Furthermore, simulated results are corroborated with results obtained in a 1800 Km. real link.