TWELP Robust 1600 bps vocoder provides high speech quality as in clear channel as well as in noisy radio channel.
Unrobust TWELP 1600 bps vocoder provides more better speech quality in clear channel, but has worse robustness to channel errors.
TWELP 1600 bps Vocoder and TWELP Robust 1600 bps vocoders are available right now as an object libraries for any DSP, RISC and other platforms.
Please visit the following page for details: