Codecs The SMV for
Wideband CDMA is based on 4 codecs: full rate at 8.5 kbit/s, half rate at 4 kbit/s, quarter rate at 2 kbit/s, and eighth rate at 800 bit/s. at full rate with clean speech. The coder works on a frame of 160 speech samples (20 ms) and requires a look ahead of 80 samples (10 ms) if noise-suppression option B is used. An additional 24 samples of look ahead is required if noise-suppression option A is used. So the algorithmic delay for the coder is 30 ms with noise-suppression option B and 33 ms with noise-suppression option A. The next evolution of CDMA speech codecs is
VMR-WB which provides much higher speech quality with
wideband while fitting to the same networks. SMV can be also used in 3GPP2 container file format –
3G2. ==References==