The standard speech coder
starts from the 64kbps PCM (Pulse Code Modulation) method adopted in ITU-T recommendation G.711 in 1972 and standardized to 32kbps ADPCM (Adaptive DPCM) and 16kbps LD-CELP (Low-Delay CELP).
A final section presents MATLAB programs for a speech coder
and a music coder.
RealSpeak Word uses a new approach to achieve high quality synthesis for predefined words and idioms based on a coding-by-synthesis model rather than the traditional method of recording the audio data and then using a speech coder
. This traditional method requires significantly more storage memory.
The speech coder
is based on a residually excited linear predictive coder, enhanced by including a long term predictor (LTP).
The research is continuing toward the design of a speech coder
capable of generating feature hypotheses for every speech sound.
are essential parts of Public Switched Telephone Networks (PSTN), Voice over Internet Protocol (VoIP), mobile communications, videoconferencing etc.
Optimizing digital speech coders
by exploiting masking properties of the human ear.
The text also includes an introduction to the properties, design, and selection of RF subsystems and antennas, as well as an introduction to speech coders
and video coders in wireless systems.
Lucent argues that the evolution to 3G networks is less about advances in optical networks, switches or radio speech coders
-- although these are all essential -- and more about how the new capabilities of 3G networks will empower consumers.
These applications require support for video coders, speech coders
, telephony middleware, JBIG standards (Joint Bi-Level Image Experts Group), MP3, software modem- and other DSP-intensive tasks in addition to supporting a real-time operating system, and system and network management tasks which are better served by a RISC processor.
Although there has been no announcement, it is clear that SASL will make new versions of its low-level speech coders
, modems and echo canceler applications available for the StarCore DSPs that Motorola and Lucent Technologies are creating, and which will initially use Motorola's M-Core instruction set.
The value of [mu] is usually chosen in the neighborhood of 0.9 for 2 bit per sample (16 kbps) speech coders