Speech analyzer
First Claim
1. Apparatus for quantizing a speech waveform and/or a waveform that is a replica of an audio signal, such as a telephone ring, a knock or a siren, comprising means for establishing N signal level bands, where N is an interger more than two, adjacent ones of said bands having common boundaries, each of said boundaries being a predetermined percentage of the peak level of a complete cycle of the waveform, means responsive to the established bands for deriving a bilevel signal having a first level while the speech signal has an amplitude lying in even numbered ones of said bands and a second level while the speech signal has an amplitude lying in odd numbered ones of said bands.
0 Assignments
0 Petitions
Accused Products
Abstract
A speech signal is analyzed by applying the signal to formant filters which derive first, second and third signals respectively representing the frequency of the speech waveform in the first, second and third formants. A first pulse train having approximately a pulse rate representing the average frequency of the first formant is derived; second and third pulse trains having pulse rates respectively representing zero crossings of the second and third formants are derived. The first formant pulse train is derived by establishing N signal level bands, where N is an integer at least equal to two. Adjacent ones of the signal bands have common boundaries, each of which is a predetermined percentage of the peak level of a complete cycle of the speech waveform. A first level of the first pulse train is derived while the first formant signal has an amplitude lying in even numbered ones of the bands; a second level is derived while the first formant signal has an amplitude lying in odd number ones of the band. The pulse trains representing the first and third formant signals are normalized relative to the second formant pulse train. Normalization is attained in each instance by counting the number of pulses in the first and third pulse trains over the interval required for the pulses in the second train to reach a predetermined number. The resulting normalized pulse trains are supplied to a memory to identify a phoneme in the speech signal or are transmitted as narrow band width signals.
-
Citations
28 Claims
- 1. Apparatus for quantizing a speech waveform and/or a waveform that is a replica of an audio signal, such as a telephone ring, a knock or a siren, comprising means for establishing N signal level bands, where N is an interger more than two, adjacent ones of said bands having common boundaries, each of said boundaries being a predetermined percentage of the peak level of a complete cycle of the waveform, means responsive to the established bands for deriving a bilevel signal having a first level while the speech signal has an amplitude lying in even numbered ones of said bands and a second level while the speech signal has an amplitude lying in odd numbered ones of said bands.
- 3. Apparatus for analyzing a speech waveform and/or a waveform that is a replica of an audio signal, such as a telephone ring, a knock or a siren, comprising formant filter means responsive to the waveform for deriving first, second and third signals respectively representing the frequency content of the speech waveform in first, second and third formants, and means responsive to the first, second and third signals for separately normalizing the first and third signals relative to the second signal.
- 18. Apparatus for analyzing a speech waveform and/or a waveform that is a replica of an audio signal, such as a telephone ring, a knock or a siren, comprising formant filter means responsive to the waveform for deriving a pair of signals respectively representing the frequency content of the speech waveform in a pair of formants, and means responsive to the pair of signals for comparing the signals representing the speech in the pair of formants.
- 22. Apparatus for analyzing a speech waveform and/or a waveform that is a replica of an audio signal, such as a telephone ring, a knock or a siren comprising means responsive to the waveform for deriving first and second pulse trains respectively indicative of the frequency of the waveform in first and second formants, and means for counting the number of pulses in the first pulse train over the interval required for the pulses in the second train to reach a predetermined number.
- 24. Apparatus for analyzing a speech waveform and/or a waveform that is a replica of an audio signal, such as a telephone ring, a knock or s siren, comprising formant filter means responsive to the waveform for deriving first, second and third signals respectively representing the frequency content of the speech waveform in first, second and third formants, means responsive to the first, second and third signals for normalizing the first signal relative to the second signal, and means responsive to the normalized first signal and a function of the third signal for deriving an indication of a phoneme in a speech waveform.
Specification