International Telephone and Telegraph Corporation

Mark Joel Schneider

John Richard Cowan

Richard J Schulman

Robert Edward Bornmann

The digital CMOS/LSI synchronous serial multiplier includes a register to store an X-bit sign magnitude multiplier in parallel. The digital multiplier number can be entered into the register either serially or in parallel. A serial N-bit 2's complement multiplicand input is provided. (X - 1) adder stages are connected in series. A control arrangement coupled to the register, the multiplicand input and the adder stages are provided to couple each of the magnitude bits of the multiplier number into a different one of the adder stages with the adder stages performing successive additions of the magnitude bits of the multiplier number to provide as an output of a last of the adder stages a serial product having M bits. A serial Y-bit 2's complement addend can be coupled to the first of the adder stages to add the addend to the product.

Digital multiplier

A computational algorithm and an implementation thereof is described herein for determining the pitch period of voiced speech in real time. All processing is performed in the time domain employing the prediction residual or error signal of a 10th-order Itakura cascade adaptive linear predictor or filter as the input signal. The output (pitch period) of the algorithm and the implementation thereof is updated each sample period based on analysis of the present and past input samples. Pitch period is determined by locating the sharp pitch peaks in the short term power of the prediction residual. The instantaneous pitch period is the time separation of two adjacent pitch peaks. The algorithm and implementation thereof employs a time moving search window and a time varying threshold level to locate pitch peaks. Various tests and procedures are incorporated into the algorithm and the implementation thereof to handle the special cases of false and missed pitch peaks. Detected errors are corrected within the algorithm and the implementation thereof by utilizing past data. Unlike the correlation or averaging methods of pitch extraction which require large amounts of storage and arithmetic operations, the time domain method of this invention requires a minimal amount of storage and only simple comparisons of amplitudes.

Growing community of inventors

Nutley, NJ, United States of America

Mark Joel Schneider