Providing channel error protection for a 2400 bps linear predictive coded voice system

The U.S. Government has developed a real-time 2400 bps Linear Predictive Coded (LPC) voice algorithm which was designed to provide maximum intelligibility and quality within the time and accuracy limitations imposed by modern high-speed minicomputers. The algorithm which resulted provides excellent intelligibility and quality when transmitted over an ideal channel. However, the speech is significantly degraded in an error environment. This paper describes several techniques for reducing the effect of channel bit errors on the synthesized speech. These techniques cause no measurable degradation of the LPC speech transmitted over an error-free channel and they require less than a one percent increase in computer execution time.