SPEECH DATA ECONDING SCHEME

Abstract

A coding scheme which uses Shannon-Fano coding for data headers to identify the type of command signal, uses a first set of formant data in the command signal to generate second sets of formant data for sound class initialization, and uses delta modulation to update the initialized sound class and for sound type transitions. The header indicates initialization of sound classes, repeat of the previous command, updating the previous command or end of word. Given types of command signals and sound classes have the same header and the data portion of the command signal defines which type of command signal is present. A unique delta modulation scheme is used wherein an increment, decrement or no change is indicated by a 11, a 00 or a 10 or 01 wherein each pair represents the delta modulation bit for a parameter, one in the present frame and one in the previous frame for that parameter. A repeat code with no data is used when the delta modulation bit for all parameters change from the previous frame.

Source: Google Patents

35 USC §181 Secrecy Order

Inventor

• 1NORMAN C. SEILER