Abstract: A telecommunication system and method having a transmitter and receiver for voice encoded signals. The receiver has a speech post-processor connected as an element before conversion of the speech from digital form and delivery of the speech to a listener. The speech post-processor processes select sequences of speech signals of a predetermined duration, and obtains the most likely estimation of a speech sequence that contains unrecognized phonemes. The speech post-processor has a recognizer and parser that receives speech signals, parses them into corresponding phonemes or unrecognized phonemes. Speech sequences of preselected duration are selected, and processed through an execution trellis implemented by a Viterbi algorithm to obtain a most likely sequence estimation for sequences which contain unrecognized phonemes, and determined phonemes replace the unrecognized phonemes. Only speech sequences with unrecognized phonemes are directed to the execution trellis.

Abstract: A digital communications system (10) includes a transmitting apparatus (12) and a receiving apparatus (14). In addition to a primary information signal (16), messages and control signals (24) are communicated for use by the equipment. To avoid the use of dedicated frequency spectrum, control channel time slots, or the degradation of forward error correction of the encoded information signal, the transmitting apparatus determines the occurrence of a silence period (28) in the information signal, then inserts the message or control signal information into the silence period. The resulting composite signal is transmitted to the receiving apparatus where message and control information is removed for use by the receiving equipment, leaving the information signal intact.

Abstract: A diversity receiving system for a differential phase shift keyed digital signal having symbols occurring in successive time periods comprises at least one antenna and a plurality of receiving branches. Each receive branch operates on a different version of the digital signal and detects different type prescribed components of the phase difference between successive symbols of the branch version. A detected prescribed component of the phase difference of each type is formed for each successive time period by processing the same type detected prescribed phase difference component signals from the receive branches.