US6691083B1
Expired / Lapsed
US
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Wideband speech synthesis from a narrowband speech signal
Assignee: British Telecommunications PLC
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Filing: 1999-03-17
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Granted: 2004-02-10
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Expires: 2019-03-17
Abstract
Abstract Wideband speech is synthesized from a bandlimited speech signal, for example from speech which has been transmitted via the public switched telephone network. Due to the nature of the vocal tract, there is a correlation between a bandlimited signal and those parts of an original wideband speech signal which are missing from that signal. Narrowband speech is characterized in terms of estimated formant frequencies provided by a peak picker. The frequency of formants in speech give a good indication, for voiced sounds, as to the shape of the vocal tract. The set of frequencies provided by the peak picker is used to access a codebook which provides synthesis parameters for use by a synthesizer.
Inventors
- 👤 Andrew Paul Breen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:42
CPC Classifications
G; G10; G10L; G10L21/00; G10L21/02; G10L21/038; G10L19/00; G10L2019/0001; G10L21/0208; G10L21/0264
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
156 words
An apparatus for synthesising speech from a bandlimited speech signal, the apparatus comprising means for extracting a spectral signal from the bandlimited signal; peak-picking means arranged to receive said spectral signal and to search a predetermined frequency range to provide a set of one or more peak frequency output values corresponding to the frequency of one or more peaks in said spectral signal; codebook means containing a plurality of codebook entries, each codebook entry comprising a set of one or more codebook frequency values and a set of one or more corresponding synthesis parameters; look-up means arranged to receive said peak frequency value set and arranged to access the codebook means to extract a required synthesis parameter set corresponding to a codebook frequency value set which is close to said peak frequency value set; and speech synthesis means arranged to receive the required synthesis parameter set and to generate speech using said required synthesis parameter set.
Claim 2
Independent Claim
156 words
An apparatus for synthesising speech from a bandlimited speech signal, the apparatus comprising means for extracting a spectral signal from the bandlimited signal; peak-picking means arranged to receive said spectral signal and to search a predetermined frequency range to provide a set of one or more peak frequency output values corresponding to the frequency of one or more peaks in said spectral signal; codebook means containing a plurality of codebook entries, each codebook entry comprising a set of one or more codebook frequency values and a set of one or more corresponding synthesis parameters; look-up means arranged to receive said peak frequency value set and arranged to access the codebook means to extract a required synthesis parameter set corresponding to a codebook frequency value set which is close to said peak frequency value set; and speech synthesis means arranged to receive the required synthesis parameter set and to generate speech using said required synthesis parameter set.
Claim 3
Dependent Claim
43 words
An apparatus according to claim 1 in which the codebook synthesis parameter set contains a synthesis parameter which relates to the amplitude of a peak in the spectrum of the synthesised speech, the frequency of the peak being outside the predetermined frequency range.
Claim 4
Dependent Claim
43 words
An apparatus according to claim 1 in which the codebook synthesis parameter set contains a synthesis parameter which relates to the frequency of a peak in the spectrum of the synthesised speech, the frequency of the peak being outside the predetermined frequency range.
Claim 5
Dependent Claim
58 words
An apparatus according to claim 1 in which the peak picking means is capable of recognising more than one peak in said spectral signal and in such an event to provide a set containing a plurality of peak frequency output values, and in which some of the codebook frequency value sets contains a plurality of codebook frequency values.
Claim 6
Dependent Claim
55 words
An apparatus according to claim 1 in which a codebook synthesis parameter set contains three synthesis parameters each relating to the amplitude of a high frequency peak in the spectrum of the synthesised speech, the frequency of the high frequency peaks being a higher frequency than the upper band limit of the predetermined frequency range.
Claim 7
Dependent Claim
67 words
An apparatus according to claim 1 in which a codebook synthesis parameter set contains a synthesis parameter relating to the frequency of a low frequency peak in the spectrum of the synthesised speech the frequency of the low frequency peak being a lower frequency than the lower band limit of the predetermined frequency range; and a synthesis parameter relating to the amplitude of the low frequency peak.
Claim 8
Dependent Claim
101 words
An apparatus according to claim 1 further comprising a pitch extracting means connected to receive the bandlimited speech signal and in the event that the spectral signal represents voiced speech to provide a pitch frequency value corresponding to the pitch of the received bandlimited speech signal; in which some of the codebook frequency value sets contain a frequency value relating to pitch; and in the event that the spectral signal represents voiced speech the lookup means is arranged to extract a required synthesis parameter set corresponding to a codebook frequency value set which is also close to said pitch frequency value.
Claim 9
Independent Claim
118 words
A method for synthesising speech from a bandlimited speech signal, the method comprising: extracting a spectral signal from the bandlimited signal; searching a predetermined frequency range of the spectral signal to provide a set of one or more peak frequency output values corresponding to the frequency of one or more peaks in said spectral signal; accessing a codebook containing a plurality of codebook entries, each codebook entry comprising a set of one or more codebook frequency values and a set of one or more corresponding synthesis parameters; determining a required synthesis parameter set corresponding to a codebook frequency value set which is close to said peak frequency value set; and synthesising speech using said required synthesis parameter set.
Claim 10
Independent Claim
118 words
A method for synthesising speech from a bandlimited speech signal, the method comprising: extracting a spectral signal from the bandlimited signal; searching a predetermined frequency range of the spectral signal to provide a set of one or more peak frequency output values corresponding to the frequency of one or more peaks in said spectral signal; accessing a codebook containing a plurality of codebook entries, each codebook entry comprising a set of one or more codebook frequency values and a set of one or more corresponding synthesis parameters; determining a required synthesis parameter set corresponding to a codebook frequency value set which is close to said peak frequency value set; and synthesising speech using said required synthesis parameter set.
Claim 11
Dependent Claim
43 words
A method according to claim 8 in which the codebook synthesis parameter set contains a synthesis parameter which relates to the amplitude of a peak in the spectrum of the synthesised speech, the frequency of the peak being outside the predetermined frequency range.
Claim 12
Dependent Claim
43 words
A method according to claim 8 in which the codebook synthesis parameter set contains a synthesis parameter which relates to the frequency of a peak in the spectrum of the synthesised speech, the frequency of the peak being outside the predetermined frequency range.
Claim 13
Dependent Claim
53 words
A method according to claim 8 in which in the event that more than one peak in said spectral signal is recognised the peak frequency output value set contains a plurality of peak frequency output values, and in which some of the codebook frequency value sets contain a plurality of codebook frequency values.
Claim 14
Dependent Claim
55 words
A method according to claim 8 in which the codebook synthesis parameter set contains three synthesis parameters each relating to the amplitude of a high frequency peak in the spectrum of the synthesised speech, the frequency of the high frequency peaks being a higher frequency than the upper band limit of the predetermined frequency range.
Claim 15
Dependent Claim
67 words
A method according to claim 8 in which a codebook synthesis parameter set contains a synthesis parameter relating to the frequency of a low frequency peak in the spectrum of the synthesised speech, the frequency of the low frequency peak being a lower frequency than the lower band limit of the predetermined frequency range; and a synthesis parameter relating to the amplitude of the low frequency peak.
Claim 16
Dependent Claim
70 words
A method according to claim 8 in which some of the codebook frequency value sets contain a frequency value relating to pitch; and in the event that the spectral signal represents voiced speech a pitch frequency value corresponding to the pitch of the spectral signal is used to determine a required synthesis parameter set corresponding to a codebook frequency value set which is also close to said pitch frequency value.
References Cited (Backward Citations)
US4283601A
Cited
USRE36478E
Cited
US5001758A
Cited
EP0336658A2
Cited
US5361278A
Cited
US5293449A
Cited
US5504833A
Cited
US5327518A
Cited
JPH06118995A
Cited
US5581652A
Cited
JPH0756599A
Cited
US5933808A
Cited
US5950153A
Cited
US6041297A
Cited
US6289311B1
Cited
US5987407A
Cited
US6311154B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2007-02-09 | 2007-08-11 | 2008-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-02-09 | 2011-08-11 | 2012-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-02-09 | 2015-08-11 | 2016-02-10 | $7700.00 | Window Closed / Lapsed |