An improved method for compressing a cyclic analog signal in which adjacent positive and negative half cycles are similar, such as an audio signal, and for reconstructing or synthesizing a new analog signal from the compressed signal. The original signal is compressed by removing one of the positive or the negative half cycles and, in a preferred embodiment, digitizing the remaining half cycles. The new analog signal is generated by sequentially applying each half cycle to an output and simultan...

Apparatus, for determining the glottal waveform of a subject, is disclosed which comprises a hard-walled, uniform, cylindrical, acoustic waveguide having a cross-sectional area commensurate with that of the vocal tract of the subject. The waveguide is terminated at one end to substantially reduce acoustic wave reflections. A microphone is positioned within the wall of the waveguide to detect and convey to suitable instrumentation the glottal waveform of the subject.

A method of compressing or expanding the frequency of signals while keeping the signals' original gross temporal relationship relies upon an electrooptical processor. An apertured mask is interposed between an area-array charge coupled device (CCD) and a light emitting diode (LED). Optical signals are emitted from the LED at a clock rate which is the same as the vertical shift rate of charge packets in the CCD. Sampling the CCD's horizontal shift register output at varying rates allows a changin...

System and method utilizing the temporal separation and amplitude differences of signals for transmitting the signals in a bandwidth corresponding to one half of the frequency range present in the signals.

Audio data is converted into a digital format at a selectable conversion rate and applied through a microprocessor into memory storage. Stored data is selectively recalled and reconverted into an analog format for reconstruction into human speech at a processing rate independent of the input storage rate. The write pointer address and the read pointer address during the storage and retrieval of data are maintained within a selected address differential in accordance with the input data rate and ...

An adaptive data compression device for compressing data having variable frequency content, including a plurality of digital filters for analyzing the content of the data over a plurality of frequency regions, a memory, and a control logic circuit for generating a variable rate memory clock corresponding to the analyzed frequency content of the data in the frequency region and for clocking the data into the memory in response to the variable rate memory clock.

Variable hangover time is provided for a speech coder (105). Voice activity within a speech message is detected (209) using a voice activity detector (VAD) (107), and a signal-to-noise ratio is calculated. A variable hangover time is calculated (215) and appended to the time in which voice activity is detected, producing an extended voice detection period. The speech coder (105) is enabled only during the extended voice detection period, thus saving power.

Random access solid state memory is used for storing and playing back audio information. Compressed audio information is downloaded to the memory from an audio information source. The operator actuates apparatus for selecting information to be played back from the random access solid state memory.

Sound information is binarized by delta modulation or adaptive delta modulation. The resulting data is subjected to pulse wide modulation and the resulting data is delivered to a reproducing device, which detects a leading edge of a received signal pulse to produce a self operation timing clock to thereby reproduce a sound. When the reproducing device detects the absence of edges for a predetermined interval after the edge detection, it turns off a power source for an analog circuit to suppress ...

In a signal encoding device, a voice signal is divided into subsignals each comprising a predetermined number of successive samples, and data trains are generated by giving initial values to a recurrence equation. The generated data trains are divided into patterns each comprising the same number of samples as the predetermined number. The distance between each pattern produced by the pattern dividing unit and each of the subsignals are calculated. The pattern that provides the smallest distance...