US4004096A
Expired / Lapsed
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Process for extracting pitch information
Assignee: United States Department of the Army
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Filing: 1975-02-18
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Granted: 1977-01-18
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Expires: 1995-02-18
Abstract
Abstract A process is described for extracting the most-likely estimate of pitch from a digitized speech signal. For each segment of speech analyzed, a measure of merit is constructed for each of several possible preselected pitch periods. These measures are periodically combined with previous measures of merit to determine a one most-likely choice of pitch period for a previous segment of speech.
Inventors
- 👤 William R. Bauer
- 👤 William A. Blankinship
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:40
CPC Classifications
G; G10; G10L; G10L25/00; G10L25/90
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
123 words
A process for extracting pitch information from a digitized speech signal comprising the steps of: selecting a plurality of values τ i , each value representative of a frequency within the speech spectrum and logarithmically spaced within said spectrum; segmenting the digitized signal into frames of predetermined length; generating, for each frame and each value of pitch period τ i , a score W t (i) representative of the cost of the cheapest sequence of pitch values ending with τ i at time t; generating for each frame an array P t (i) representative of the index of the immediately preceeding pitch period in said cheapest sequence, and selecting for the current frame that τ i for which W t (i) is minimum.
Claim 2
Dependent Claim
123 words
A process for extracting pitch information from a digitized speech signal comprising the steps of: selecting a plurality of values τ i , each value representative of a frequency within the speech spectrum and logarithmically spaced within said spectrum; segmenting the digitized signal into frames of predetermined length; generating, for each frame and each value of pitch period τ i , a score W t (i) representative of the cost of the cheapest sequence of pitch values ending with τ i at time t; generating for each frame an array P t (i) representative of the index of the immediately preceeding pitch period in said cheapest sequence, and selecting for the current frame that τ i for which W t (i) is minimum.
Claim 3
Dependent Claim
87 words
The method of claim 1, wherein generating the score W t +1 (i) includes selecting a first group of values A(t+1, i) representative of the intrinsic cost of choosing τ i at time t+1, selecting a second group of values f t (j, i) representative of the cost of changing from pitch τ j at time t to τ i at time t + 1, and deriving W t +1 (i) by minimizing, with respect to j, the function A(t+1, i) + W.sub.t (j) + f(i, j).
Claim 4
Dependent Claim
26 words
The method of claim 2 wherein selecting the group of values f t (i, j) further includes selecting a group of values α t | i-j|.
Claim 5
Dependent Claim
24 words
The method of claim 3 further including the step of selecting the value α t according to the function α.sub.t = 2/5[min A(t+1, i)].
Claim 6
Dependent Claim
31 words
The method of claim 4, wherein generating the score W t (i) and the array P t (i) includes the step of updating said score and said array once per frame.
Claim 7
Dependent Claim
29 words
The method of claim 5 including the step of storing the array P t (i) for the number of frames by which the pitch decision is to be delayed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-01-18 | 1980-07-19 | 1981-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-18 | 1984-07-19 | 1985-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-18 | 1988-07-19 | 1989-01-18 | $7700.00 | Window Closed / Lapsed |