Lincoln Low-Rate Vocoder: A 1200/2400 bps LPC-10 Voice Terminal

摘要

The following is a description of a low data rate voice terminal. The unit uses an LPC-10 algorithm which provides a 2400 bps NATO standard compatible mode and a 1200 bps frame-fill mode. The unit has an RS-449 digital interface with MIL-STD-188-114 levels. The user operates the unit from a telephone instrument with a PTT handset. The user interface models an augmented combination of an FM transceiver and a telephone to inform the user of the state of the data communications equipment in a natural manner. These protocols cover the full and half duplex channels. The unit exhibits a DRT (intelligibility) score of 91.1% at 2400 bps and 88.7% at 1200 bps in benign acoustic environments. (Author)