WO1991006091A1 - Lpc based speech synthesis with adaptive pitch prefilter - Google Patents
Lpc based speech synthesis with adaptive pitch prefilter Download PDFInfo
- Publication number
- WO1991006091A1 WO1991006091A1 PCT/US1990/005191 US9005191W WO9106091A1 WO 1991006091 A1 WO1991006091 A1 WO 1991006091A1 US 9005191 W US9005191 W US 9005191W WO 9106091 A1 WO9106091 A1 WO 9106091A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- signal
- pitch
- excitation signal
- speech
- excitation
- Prior art date
Links
- 230000015572 biosynthetic process Effects 0.000 title claims description 10
- 238000003786 synthesis reaction Methods 0.000 title claims description 10
- 230000003044 adaptive effect Effects 0.000 title description 5
- 238000011045 prefiltration Methods 0.000 title description 4
- 230000005284 excitation Effects 0.000 claims abstract description 26
- 238000000034 method Methods 0.000 claims description 8
- 238000001914 filtration Methods 0.000 claims description 6
- 230000002194 synthesizing effect Effects 0.000 claims description 3
- 230000006870 function Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000008447 perception Effects 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
- G10L19/00—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
- G10L19/04—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis using predictive techniques
- G10L19/26—Pre-filtering or post-filtering
Definitions
- This invention relates generally to speech synthesis, and more particularly to linear predictive coding based speech synthesis.
- the synthesis of speech through use of a linear predictive coding (LPC) based platform is known in the art.
- a prior art radio that embodies such a platform is depicted generally in Fig. 1 by the reference numeral 100.
- the radio (100) receives a speech coded signal (101) through an appropriate energy transducer (102), such as an antenna.
- An RF unit (103) converts the received signal (101) to baseband and demodulates the signal to recover the speech coded information.
- a parameter decoder (105) develops control parameters for various subsequent processes from this information.
- An excitation source (104) as described above utilizes the parameters provided to it to create an excitation signal and then provides that excitation signal (which excitation signal includes pitch information that has been inserted by a pitch filter) to an LPC filter (106) which in turn provides, at it's output, a synthesized speech signal.
- This synthesized speech signal is then filtered in an adaptive pitch postfilter (107) and an adaptive spectral postfilter (108), as well as a post emphasis filter (109), to enhance the perception of natural speech and to minimize the impact of various distortions and artifacts introduced in the synthesis process.
- the enhanced synthesized speech signal is then properly processed in an audio processing unit (111) and rendered audible through an appropriate audio transducer (112).
- the pitch postfilter (107) serves an important function, in that it provides additional control of the pitch content of the synthesized speech. Without this filter, the resultant synthesized speech product may be rougher and of lower quality. Notwithstanding this important benefit, the pitch postfilter (107) frequently contributes artifacts to the resultant synthesized speech, which artifacts can themselves noticeably disturb the perception of natural speech. Accordingly, a need exists for providing appropriate pitch enhancement filtering in an LPC based speech synthesizing unit that minimizes a concurrent perceptible expression of artifacts in a resultant synthesized speech signal.
- the pitch enhancement postfilter is moved from a position of processing the LPC filter output to a position where it processes the excitation input to the LPC filter.
- the subsequent processing of the LPC filter itself functions to minimize the perceptible effect of any artifacts introduced by the pitch enhancement prefilter in the resultant synthesized speech signal.
- Fig. 1 comprises a block diagram depiction of a prior art embodiment of a radio receiver having LPC based speech synthesis
- Fig. 2 comprises a block diagram depiction of a radio having LPC 3as ⁇ d speech synthesis in accordance with the invention.
- a radio embodying the invention includes an antenna (102) for receiving a speech coded signal (101 ).
- An RF unit (103) processes the received signal to recover the speech coded information.
- This information is provided to a parameter decoder (105) that develops control parameters for various subsequent processes.
- An excitation source (104) as described above utilizes the parameters provided to it to create an excitation signal.
- This resultant excitation signal from the excitation source (104) is provided to a pitch prefilter (201) that functions to filter the pitch information contained in the excitation signal.
- the resultant filtered signal then passes to the LPC filter (106) which yields a
- this resultant signal is then further processed in an adaptive spectral postfilter (108) and post emphasis filter (109) to further enhance the quality of the synthesized speech, and is then processed in an audio processing unit (111 ) and rendered audible by an audio transducer (112).
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Multimedia (AREA)
- Health & Medical Sciences (AREA)
- Audiology, Speech & Language Pathology (AREA)
- Human Computer Interaction (AREA)
- Computational Linguistics (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Compression, Expansion, Code Conversion, And Decoders (AREA)
- Noise Elimination (AREA)
- Filters That Use Time-Delay Elements (AREA)
- Stereophonic System (AREA)
- Reduction Or Emphasis Of Bandwidth Of Signals (AREA)
- Transmission Systems Not Characterized By The Medium Used For Transmission (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP90916987A EP0496829B1 (en) | 1989-10-17 | 1990-09-17 | Lpc based speech synthesis with adaptive pitch prefilter |
DE69033672T DE69033672T2 (en) | 1989-10-17 | 1990-09-17 | LANGUAGE SYNTHESIS BASED ON THE LPC METHOD WITH ADAPTIVE PITCH PRE-FILTER |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US42287189A | 1989-10-17 | 1989-10-17 | |
US422,871 | 1989-10-17 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1991006091A1 true WO1991006091A1 (en) | 1991-05-02 |
Family
ID=23676771
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1990/005191 WO1991006091A1 (en) | 1989-10-17 | 1990-09-17 | Lpc based speech synthesis with adaptive pitch prefilter |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0496829B1 (en) |
CN (1) | CN1051100A (en) |
AU (1) | AU644119B2 (en) |
CA (1) | CA2066568A1 (en) |
DE (1) | DE69033672T2 (en) |
WO (1) | WO1991006091A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19629946A1 (en) * | 1996-07-25 | 1998-01-29 | Joachim Dipl Ing Mersdorf | LPC analysis and synthesis method for basic frequency descriptive functions |
US5946651A (en) * | 1995-06-16 | 1999-08-31 | Nokia Mobile Phones | Speech synthesizer employing post-processing for enhancing the quality of the synthesized speech |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3328080B2 (en) * | 1994-11-22 | 2002-09-24 | 沖電気工業株式会社 | Code-excited linear predictive decoder |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4969192A (en) * | 1987-04-06 | 1990-11-06 | Voicecraft, Inc. | Vector adaptive predictive coder for speech and audio |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4220819A (en) * | 1979-03-30 | 1980-09-02 | Bell Telephone Laboratories, Incorporated | Residual excited predictive speech coding system |
-
1990
- 1990-09-17 DE DE69033672T patent/DE69033672T2/en not_active Expired - Lifetime
- 1990-09-17 AU AU67256/90A patent/AU644119B2/en not_active Expired
- 1990-09-17 CA CA 2066568 patent/CA2066568A1/en not_active Abandoned
- 1990-09-17 EP EP90916987A patent/EP0496829B1/en not_active Expired - Lifetime
- 1990-09-17 WO PCT/US1990/005191 patent/WO1991006091A1/en active IP Right Grant
- 1990-10-15 CN CN 90108434 patent/CN1051100A/en active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4969192A (en) * | 1987-04-06 | 1990-11-06 | Voicecraft, Inc. | Vector adaptive predictive coder for speech and audio |
Non-Patent Citations (1)
Title |
---|
See also references of EP0496829A4 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5946651A (en) * | 1995-06-16 | 1999-08-31 | Nokia Mobile Phones | Speech synthesizer employing post-processing for enhancing the quality of the synthesized speech |
US6029128A (en) * | 1995-06-16 | 2000-02-22 | Nokia Mobile Phones Ltd. | Speech synthesizer |
DE19629946A1 (en) * | 1996-07-25 | 1998-01-29 | Joachim Dipl Ing Mersdorf | LPC analysis and synthesis method for basic frequency descriptive functions |
Also Published As
Publication number | Publication date |
---|---|
AU6725690A (en) | 1991-05-16 |
AU644119B2 (en) | 1993-12-02 |
CN1051100A (en) | 1991-05-01 |
EP0496829B1 (en) | 2000-12-06 |
CA2066568A1 (en) | 1991-04-18 |
DE69033672D1 (en) | 2001-01-11 |
EP0496829A1 (en) | 1992-08-05 |
DE69033672T2 (en) | 2001-05-10 |
EP0496829A4 (en) | 1993-08-18 |
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