Orthogonal transformer and apparatus operational thereby

[54] ORTHOGONAL TRANSFORMER AND APPARATUS OPERATIONAL THEREBY

[75] Inventor: Masao Watari, Tokyo, Japan

[73] Assignee: NEC Corporation, Tokyo, Japan

[21] Appl. No.: 177,799

[22] Filed: Apr. 6,1988

Related U.S. Application Data

[63] Continuation of Ser. No. 56,017, Jun. 1, 1987, abandoned, which is a continuation of Ser. No. 599,119, Apr. 11, 1984, abandoned.

[30] Foreign Application Priority Data

Apr. 11, 1983 [JP] Japan 58-63186

Apr. 20, 1983 [JP] Japan 58-69474

[51] Int. Q.* G06F 15/332

[52] U.S. CI :... 364/727

[58] Field of Search 364/727, 726, 725;

381/31

[56] References Cited

U.S. PATENT DOCUMENTS

3,881,097 4/1975 Lehmann 364/726

4,038,539 7/1977 Van Cleave 364/724

4,052,565 10/1977 Baxter et al 364/727

4,446,530 5/1984 Tsvboka 364/725

4,495,620 1/1985 Steele et al 381/31

4,510,578 4/1985 Miyaguchi et al 364/725

Apparatus for obtaining an orthogonal transformer for use in signal analysis. This apparatus is especially useful in cepstral analysis where vocal tract characteristics of a signal are separated from a sound source. A buffer memory 10 temporarily stores input time series data and an orthogonal transformation is carried out by an orthogonal transform means 20 by multiplying each predetermined data read sequentially out of the buffer memory 10 by a predetermined twiddle factor. A controller 30 is used to specify the data read out of the buffer memory 10 and for giving the twiddle factor a value of 1 and r/2' corresponding to the magnitude of the real and imaginary part of the twiddle factor. Cepstrum information is obtainable using simple hardware to analyze the data generated by the orthogonal transformer.

15 Claims, 9 Drawing Sheets