Abstract: A siren detection system, particularly suited for installation in an automobile for providing a warning to the driver when an emergency vehicle is operating a siren in the vicinity of the automobile, utilizes a microphone on the automobile to detect the siren signals. An analog-to-digital conversion of the signal obtained from the microphone is supplied to a digital signal processor which is programmed to provide high selectivity of the frequency of the input signals, with improved noise rejection and improved frequency determination.

Abstract: A waveform recognition system including a plurality of detectors of features having the combined presence at a plurality of instants spaced at predetermined intervals relative to each other in time of instantaneous amplitudes each satisfying respectively predetermined constraints; apparatus for assigning a plurality of labels and corresponding confidence measures to each of successive portions of the waveform in dependence on the features detected in the portions and storing each label in a buffer corresponding to the rank of the confidence with which the label is assigned relative to other labels assigned to the same portion of data and apparatus for outputting labels from that buffer containing labels assigned with the highest confidence whose confidence measures are in a predetermined relationship with those of adjacent labels in the same buffer when the confidence measures of labels in other buffers containing labels assigned with confidence measures of lower rank satisfy predetermined conditions.

Abstract: A speech-controlled device produces a visual representation (via a typewriter, printer or display device) of a spoken input. The device operates in real time without speaker-dependence, and comprises a fast speech analyzer (FSA) for analyzing the speech input as relatively fast speech and a slow speech analyzer (SSA) for analyzing the speech input as relatively slow speech. In a first embodiment, a selector is responsive to a determination that the speech input is relatively fast or slow speech for selecting the output of the FSA or SSA, as appropriate. In a second embodiment, an enable circuit is responsive to a determination that the speech input is relatively fast or slow for enabling a corresponding one of the analyzers for operation.

Abstract: Adaptive bit allocation to the channels of a sub/band coder (or to the coefficients of a transform coder) by using a fixed set of numbers of bits, only the selection of those channels to which the available bits are assigned being varied.

Abstract: A method of and a device for deriving formant frequencies from a part of a speech signal. For determining the formant frequencies from a part of a speech signal located within a given time interval, the Split Levinson algorithm is used. In the Split Levinson algorithm a higher order singular predictor polynomial (P.sub.k (z)) is each time determined in successive recursion steps. After the last recursion step the formant frequencies (f.sub.1, f.sub.2, . . . ) are determined.

Abstract: In an encoder operable in response to a discrete pattern signal divisible into a succession of segments to produce an output code sequence, a pitch parameter and a spectral parameter are extracted in a parameter calculator from each segment and from a spectral interval. In an excitation pulse producing circuit, each spectral interval is divided into a plurality of subframes, namely, pitch periods with reference to the pitch parameter to divide each segment. A minor group of excitation pulses is calculated from the segment at every subframe to form a major group of the excitation pulses in the spectral interval. The excitation pulses of the major group are reduced in number with reference to adjacent ones of the minor groups in each spectral interval and are modified into a succession of modified excitation pulses. The modified excitation pulses are combined with the spectral parameter into the output code sequence.

Abstract: A speech analyzing and synthesizing apparatus includes a sampling circuit for sampling an inputted speech signal, a speech analyzer for analyzing and coding the inputted speech signal, and a speech synthesizer for decoding the speech signal coded by said speech analyzer into a synthesized speech, whereby the average code length can be advantageously shortened to realize a low capacity memory and a well-analyzed and synthetized speech. Moreover, a speech recording apparatus is provided wherein a soundless section in the inputted speech signal is compressed by real time, and even a weak short-time portion in the sounded section of an inputted speech signal is not erroneously judged to be soundless, but is coded as a sounded portion.

Abstract: An echo effect is synthesized in a coded digital sound signal. An input sound signal is stored as a plurality of sequential frames of similar duration, each frame (n) having characteristics including an energy (E). A delay period (d) is selected as equal to a number of time. For each frame (n) later than the duration of frames of the delay (d), the energy E(n) of the frame is compared to an attenuated energy aE(n-d) of an earlier frame (n-d), which is earlier in time than frame (n) by a number of frames equal to the delay (d). If the energy E(n) is less than the attenuated energy aE(n-d) of the earlier frame, the current frame is replaced in an output sequence with a new frame having the non-energy characteristics of the earlier frame and the attenuated energy.

Abstract: Speech is coded such that it can be generated by a pulse excitation sequence filtered by an LPC (linear preductive coding) filter. The sequence contains, in each of successive frame periods, pulses whose positions and amplitudes may be varied. These variables are selected at the coding end to reduce the error between the input and regenerated speech signals. The selection process involves derivation of an initial estimate followed by an iterative adjustment process in which pulses having a low energy contribution are tested in alternative positions and transferred to them if a reduced error results.

Abstract: Apparatus for use by a broker including a memory for holding a number of market prices each corresponding to a security or a commodity. A speech synthesizer provides that prices may be quoted to customers in a synthesized human voice. A telephone interface connects outside calls to a DTMF transceiver which is in turn connected to a programmed microprocessor unit so that a caller may key in instructions or information. Instructions for price quotations result in the price for the selected security or commodity being reported to the caller in a synthesized human voice. The apparatus is also capable of monitoring price triggers and reporting violations of price triggers by calling a predetermined telephone number and reporting the violation in a synthesized human voice. Also, price requests are logged and the unit is responsive to an instruction keyed in by a broker through his telephone to report the contents of the log over the telephone in a synthesized human voice.

Abstract: An acoustic processing unit for a speech recognition system is characterized in that the parameters are extracted from the speech data, including correlation functions, the zero crossing number of the original waveforms, the zero crossing number of the differential waveforms, and the average level of the waveforms. A suitable threshold is selected from a plurality of thresholds preliminarily stored, depending on the inputted speech volume level. The inputted speech volume level of the speaker is detected so that feedback of the detected volume level is obtained. The selected threshold set is then compared with each of the parameters to thereby make the phonemic classification. Because the plurality of threshold sets are thus automatically selected depending on the inputted speech volume level, flexible phonemic classification can be obtained to exactly detect the speech sections.

Abstract: Apparatus that solves the problem of pattern recognition in a temporal signal that is subject to distortions and time warp. The arrangement embodying the invention comprises a neural network, an input interconnection network, and a plurality of signal modification circuits. A plurality of input leads delivers a preselected characteristic stimulus to associated signal modification units, and in response to an applied stimulus, each signal modification unit develops a plurality of output signals that begins at the time of stimulus application, rises to a peak, and decays thereafter. The mean time delay of each output (time to reach the peak) is different for each of the modification unit output signals. The outputs of the signal modification units are applied to the input interconnection unit wherein connections are made in accordance with the sequences that are to be recognized.

Abstract: A speech recognizing device capable of recognizing a speech uttered in a noisy environment. The device uses low frequency data which are hardly susceptible to spectrum fluctuations for those portions of an input speech which are similar to vowels, while using entire frequency data for the other portions of the speech.

Abstract: From a speech signal, spectrum information as a plurality of line spectrum data, pitch position data and amplitude data are extracted. Each of the sinusoidal wave signals of different frequencies is allotted to the predetermined line spectrum data. The frequency of the sinusoidal wave signal is changed with the pitch position being the boundary. The plurality of sinusoidal wave signals are added and the added result is modulated by the amplitude data to transmit the modulated signal as the transmission data. The line spectrum data, the pitch position data and amplitude data are extracted from the modulated signal. The replica of the speech is produced on the basis of these extracted data.

Abstract: An interactive patient assistance device houses both preselected doses of medication and a physical testing device. Both medication and the testing device are normally retained within separate compartments within the device away from access by the patient. The device keeps track of medication and diagnostic testing schedules. The device is also capable of receiving and interpreting verbal commands of the patient. The device makes a preselected dose of medication available to the patient in response to either the medication schedule or the receipt of a verbal command by the patient. Likewise, the testing device is made available to the patient in response either to the testing schedule or the receipt of a verbal command from the patient.

Abstract: The input pattern to a pattern recognition system is defined as a candidate graph composed of several possibly valid category strings. The most valid category string is selected as the input pattern. Each category string is composed of linked category segments, each category segment being bounded by category nodes or branching points to which are connected one or more category segments. The most valid category string is developed by establishing the most valid midway path from the start node and extending to the terminal node. A most valid midway path to each midway node (n) is established by using the minimum valid estimation value determined for all possible midway paths from the start node to the midway node (n).

Abstract: High speed computing apparatus for performing real time data compression of analog voice data or digital data to be transmitted over a data link. The incoming data stream is divided into blocks of digital data and the blocks are subdivided into digital samples or elements to be compressed. Each sample is analyzed individually to determine its estimated variance and the marginal return to be gained by alloting the sample one or more of the bits to be employed to define the block of digital data. The bits are assigned samples having the highest estimated variance factor so that an optimum allocation of bits to individual samples is achieved with variable ratio data compression. The allocated bits are employed to encode the samples during real time data compression and transmission.

Abstract: Message storage capacity is provided on memory modules, the number of modules being expandable to increase the capacity of the system. Each module has digital memory which is organized with a plurality of message units, each message unit including a number of successive memory bytes for storing respective messages. A desired message is accessed by stepping through the message units to the desired location having the start of the desired meassage, skipping the intervening bytes. The message is then read out at the system clock rate. The memory of each module is preferably addressed by a corresponding counter which has a lower order control input for counting up at one memory byte per count, and a higher order control input for counting up at an accelerated rate of one message unit per count.

Abstract: A pitch detector to adjust long term prediction in a pulse excitation speech coder. A residual signal r(n) is first derived from the speech signal s(n) by short term filtering. Then, r(n) is processed to calculate a prediction error signal e(n) which is subsequently pulse excitation encoded. The processing of e(n) entails prediction of a residual by measuring a pitch related factor M, employing two steps. First calculating a coarse M value through peak clipping and sign transition detection, and then adjusting the M value by autocorrelation--calculations about the roughly spaced peaks.

Abstract: In circuits for generating rapidly changing, yet smooth and controlled, control signals in response to transient signals for use in audio compressors and expanders, a steady-state portion of the control circuit includes first and second smoothing stages (alternatively, a single stage may be employed) and an overshoot suppression portion of the control circuit rapidly charges the capacitor in the steady-state smoothing stage from which the control voltage is derived. A first additional overshoot suppression circuit provides further charging of the capacitor in response to low frequency signal components. Modulation control signals, which make the compressor or expander less susceptible to control by stop-band signal components, are combined in opposition to the signals in the steady-state and overshoot suppression portions of the control circuit.