Low-Cost Voice Coder Delivers Toll Quality

Designed as a compliment to the company's AMBE-2000 vocoder, the AMBE-2020 vocoder chip supports full-duplex operation, bit rates from 2 to 9.6 kb/s, and provides toll-quality speech at 4 kb/s. With variable-rate FEC built in, the device offers convolution codes with up to four bits of soft decision decoding allowing it to achieve peak performance in degraded channel conditions that include significant bit errors. The built-in Viterbi decoder offers rates as low as R=1/4 for intelligible speech with up to 20% BER. Other features include automatic voice-activity detection, adaptive comfort noise insertion, and DTMF detection and generation. Available in 100-pin TQFPs, pricing is $16 each.