United States Patent [19] [li] Patent Number: 4,627,090
Smith, III et al. [45] Date of Patent: Dec. 2,1986
[54] AUDIO FREQUENCY MULTIPLICATION DEVICE
[75] Inventors: Jay Smith, III, Pacific Palisades;
Gerald S. Karr, Venice, both of Calif.
[73] Assignee: Smith Engineering, Culver City,
Calif.
[21] Appl. No.: 756,734
[22] Filed: Jul. 19,1985
Related U.S. Application Data
[63] Continuation of Ser. No. 399,690, Jul. 19, 1982, abandoned.
[51] Int. Q." G10L5/00
[52] U.S. a 381/34; 381/40
[58] Field of Search 381/29-35
[56] References Cited
U.S. PATENT DOCUMENTS
3,816,664 6/1974 Koch 381/30
4,053,712 10/1977 Reindl 381/30
4,091,242 5/1978 Carrubba et al 381/30
4,370,524 1/1983 Hiraguri 381/29
OTHER PUBLICATIONS
Specifications Continuously Variable Slope Delta
Modulator/Demodulator, Motorola MC3417.
VSC: Variable Speech Control M8 Module.
Primary Examiner—E. S. Matt Kemeny
Attorney, Agent, or Firm—Price, Gess & Ubell
[57] ABSTRACT
A signal processing device for frequency multiplication of an analog signal by an adjustable multiplication factor. The input analog signal is digitized using a delta modulator and read into a random access memory at a first clock rate. The data is read out of the memory at second clock rate and then converted back to an analog output signal. The multiplication factor is a function of the adjustable ratio of the two clock rates.
6 Claims, 7 Drawing Figures
