Abstract: Speech signals are analyzed by correlating a sequence of samples to derive a sliding average magnitude difference function (SAMDF) whereby histograms are formed which are compressed and normalized to form histogram sequences representing the speech signal for comparison and recognition.

Abstract: A method and apparatus for generating a signal transformation useful in signal processing. According to the preferred embodiment, a signal, e.g., a speech waveform, is first converted into a sequence of digital data samples, and a reference position along a first sub-part of the sequence is then selected. A "weighted" histogram corresponding to the reference position is then generated according to a correlation function. Thereafter, a new reference position is selected, for example, at a sub-part of the sequence located a pitch period of the signal from the original reference position, and an additional histogram is generated for this sub-part. The plurality of histograms comprise the transformation of the signal, which retains a substantial part of the informational content of the original signal. Therefore, the transformation is then used as the signal itself in signal processing applications such as speech compression and synthesis.

Abstract: A real time cochlear implant processor (10) receives an audio input signal and extracts spectrum segments by operation of bandpass filters (18, 20). In each channel temporal circuitry detects the zero slope points of the filtered audio input signal and generates a control signal which operates a gate (66). Amplitude circuitry includes a reference voltage source for providing positive and negative polarity signals for a first mode of operation. The reference signals are routed through the gate (66) by the control signals. In a second mode of operation the audio input signal, after logarithmic amplification, is passed through the gate (66) by operation of the control signals. In a third mode of operation the audio input signal is squared through infinite clipping and the resulting signal is gated by the control signals through the gate (66). The outputs of the channels are combined in a summing circuit (78) and passed through a buffer (82) to produce a driver signal for an auditory implant electrode.

Abstract: A method of human-machine interactive instruction with the aid of a digital computer is disclosed. The first step is providing the computer with a data base of a series of questions and answers which can be reproduced and thereafter individualized by student use by (i) providing the digital computer with a keyboarded typed question, (ii) providing the computer with a keyboarded typed answer, (iii) speaking the correct answer a plurality of times to generate relational signals for master template of the correct answer in digital form, and (iv) correlating the master template with the corresponding keyboarded typed answer.

Abstract: Recognition of human speech is carried out by storing a template for each unit of speech to produce a dictionary of stored words and phrases. A given speech signal is converted to produce a template which is compared to the stored template to find the closest comparison. The word or phrase corresponding to the identified template is produced and displayed to complete the recognition of the speech signal. The speech signal is processed to produce two separate frequency components. The frequency components are processed to produce a DC signal proportional to the frequency of the frequency component. The frequency components are also rectified to produce amplitude signals corresponding to the envelope of the frequency components. The products [F.sub.1 ][F.sub.2 ] and [A.sub.1 ][A.sub.2 ] and ratios F.sub.1 /F.sub.2 and A.sub.1 /A.sub.2 of the pairs of frequency and amplitude signals are produced to generate a plurality of relational signals which comprise the templates corresponding to each speech signal.