Adaptive differential, pulse code modulation sound generator

• US 4,989,246 A
• Filed: 03/22/1989
• Issued: 01/29/1991
• Est. Priority Date: 03/22/1989
• Status: Expired due to Fees

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Peng, Shie-Ming, Wu, Der-Chwan, Wan, Shyue-Yun
• Primary Examiner(s): KEMENY, EMANUEL
• Application Number:
  US07/326,993
• Time in Patent Office: 678 Days
• Field of Search: 381/40, 360/8
• US Class Current: 704/212
• CPC Class Codes: G10L 19/012 Comfort noise or silence coding
• CPC Class Codes: H03M 7/3046 adaptive, e.g. adaptive differential pulse code modulation [ADPCM]

Abstract

A sound generator for storing and reproducing audio signal with reduced memory storage, which is accomplished by: (a) the technique of Adaptive Differential Pulse Code Modulation (ADPCM), and (B) the elimination of silence period from memory storage but regenerating the silence signal at output.

Claims

1. A storage and generation system for sound signal having silence and repetition periods, comprising

means for converting said sound signal into digital codes using adaptive differential pulse code modulation (ADPCM) technique,

means for storing in a memory said digital codes except said silence periods and repetition periods,

means for converting said stored digital codes into analog signal together with said silence period and repetition periods,

means for converting said ADPCM code in a read only memory based on different signal content,

said means for storing said ADPCM code and said means for converting said digital signals including:

(a) Oscillator for generating a basic clock pulse for whole said system,

(b) Timing generator for generating clocks for different functional blocks,

(c) Control circuit for controlling the start, repetition and end of said sound signal,

(d) ROM1 for storing said sound signal codes,

Address Decoder for outputting decoded addresses from said ROM1,

(f) Data Decoder for decoding said digital codes from said ROM1,

(g) ROM2 for storing stepsize values,

(h) ADDER1 for adding or subtracting data from said decoder and outputting results to addresses of said ROM2,

(i) ADDER2 for adding or subtracting said size values,

(j) Data Code Counter for controlling said ADDER2 for continuous addition,

(k) DAC for transferring the signal from said ADDER2 to corresponding analog signal.

2. A storage and generating system for sound having silence and repetition periods as described in claim 1, wherein said Address Decoder and said ROM1 can automatically generate a signal such as 0000 which is decoded by said address decoder.

3. The claim 1 storage and generating system for sound having silence and repetition periods wherein said ADDER 2 adds a digital signal, such as 0000, appears.