Masayuki Misaki

Apparatus and method for performing speech rate modification and improved fidelity

In a speech rate modification system and method, correlation functions between different segments of input speech signal are computed by a correlator (17), the amplitude of the input signal is controlled by two multipliers (19, 20) which multiply the input speech signal by an increasing window function and by a decreasing window function, or vice versa, respectively, produced by a window function generator (18), and then output signals of the multipliers (19, 20) are added to each other by an adder (21) at such a relative delay within one unitary segment (T) as to maximize the value of the correlation function, and the input voice signal and the output of the adder (21) are selected by a multiplier (22), to be issued as a rate-modified speech signal.

Apparatus and method for speech signal processing

In an apparatus for speech signal processing, first a coefficient calculation is performed to determine a value for suppressing a change of level of an input signal. Next, an input signal delay is performed to delay the input signal by a time required for the coefficient calculation. Then an output of the input signal delay is multiplied by the value obtained by the coefficient calculation, thereby obtaining an output signal.

Time-scale modification of speech signals using cross-correlation functions

A high-performance method of modifying the time scale of speech signals into an arbitrary time scale was developed. It requires substantially reduced arithmetic operations. This process is performed within a time domain where the time-scale expansion or compression is performed by inserting or substituting composite segments into or from an original input signal, and the length of the segment is optimized by an objective evaluation process. A monosyllable articulation test comparing this method with a conventional time-scale modification method performed by a simple modification of sampling frequency proved that there are definite advantages to using the new method. >

Apparatus and method for speech signal level change suppression processing

A level measuring circuit first measures a level of an input speech signal. Next, a coefficient calculating circuit determines a value for suppressing a change of the level of the input speech signal on the basis of an output of the level measuring circuit. Then an input speech signal delay circuit delays the input speech signal by a time required for processing in the level measuring circuit and the coefficient calculating circuit. Finally a multiplying circuit multiplies an output of the input speech signal delay circuit by an output of the coefficient calculating circuit to obtain an output speech signal in which changes in level of the input speech signal are suppressed.

Time-scale Modification Of Speech Signals Using Cross-correlation

This paper describes a method for high-quality, low computation, time-scale modification of speech signals at an arbitrary time-scale factor. A syllable articulation test comparing our method to time-scale compressionlexpansion by simply modifying sampling frequency clearly showed the superiority of our method.

Solid State Recorder Using Hierarchial Audio Signal Coding Method

In this paper we described a solid state recoryler which can automatically adapt the bit rate to recording time and memory capacity, using hierarchial audio coding method ard random accessibility of solid state memory.