An improved speech compressor provides frequency transformation by passing speech signals through an analog shift register and controlling the shift rate of the register with a linearly varying periodicity with noise cancellation of the characteristic noise in the shift registers and the control of the sample period and output blanking to improve the signal output characteristic and minimize noise components therein. The system provides a single compression-expansion manual control which varies ...

This relates to a digital speech detector applicable to a TASI communication system wherein the detector detects the presence or absence of speech in a plurality of digital code groups each of which indicate a quantized amplitude of a speech sample. The speech detector is divided into two portions. The first portion is an instantaneous detector that detects the quantized amplitude of each of the code groups in sequence and produces an up count signal when the detected quantized amplitude is grea...

A film plate with a series of signal patterns representative of successions of individual speech-sound wave units stored thereon is disposed in front of a cathode ray tube having an optical fiber face plate. By appropriately controlling the scanning system of the cathode ray tube, the scanning beam is directed to the pattern of a signal representing the speech-sound wave unit on the film plate which is required to be read out. The intensity of the electron beam itself is controlled in such a man...

Speech signal energy from an undesired source is suppressed by extracting from the undesired signal a delay parameter and a gain parameter. These parameters control a delay and gain network through which both the desired and undesired signals are routed. The delayed, amplified signal, when applied to a subtractor along with the undelayed signal, suppresses the undesired signal. The invention is applied to several hands-free telephony situations and to the suppression of one of two speakers in a ...

A speech-controlled switching arrangement for communication systems in which the speech signals are transmitted in the form of digital signals obtained by code modulation, comprising a plurality of pulse group analyzers coupled to respective transmission channels from which analyzers the output pulses are applied to a comparator circuit after integration for the purpose of generating a switching control signal, while each pulse group analyzer is provided with a digitally defined threshold charac...

A telephone recorder including a single relay having two windings. The first winding is connected in series with the telephone and the telephone line. Since there is no d.c. path through the first winding until the telephone receiver is picked up, telephone call or ringing signals do not operate the relay. However, when the receiver is picked up, the relay is energized to close contacts to initiate operation of the recorder. Speech signals on the telephone line pass through the first relay windi...

The generation of a set of a certain kind of coefficients related to the speech signal is obtained by simultaneously operating upon a sample of the speech signal with a set of orthogonal random functions derived from a white noise source and the white noise itself. These coefficients are sequentially AM or FM modulated for transmission by any suitable means. The transmitted signal is received and demodulated and sequentially processed through the system of this invention to recover the coefficie...

To reduce power consumption and operation frequency, a speech synthesizer comprises a volume control unit to receive a control signal and generate a control bias, a signal transform unit to receive the control bias Vbias and a series of digital speech codes and under the control of the most significant bit of the digital speech codes to transform the other bits of the digital speech codes or its inverse into an analog signal, and a current output unit to receive the analog signal from the signal...

A clipped input speech waveform is divided into a plurality of a series of signals by means of a wavelet transform such as the Daubechies wavelet transform, which are then scaled or otherwise processed to reduce the effects of clipping, prior to reconstruction of the speech waveform using the inverse transform.

In order to recognize input speech by analyzing the input speech at a predetermined time interval, extracting feature vectors and calculating likelihood value of a reference pattern model of each category to be recognized. A first probability calculation means calculates a probability that a first hidden Markov model having internal state number as output symbol for each of categories to be recognized outputs an internal state number. A second probability calculation means calculates a probabili...