NOTE: This item is not available outside the Texas A&M University network. Texas A&M affiliated users who are off campus can access the item through NetID and password authentication or by using TAMU VPN. Non-affiliated individuals should request a copy through their local library's interlibrary loan service.
Robust tree coding combined with harmonic scaling of speech
dc.contributor.advisor | Gibson, Jerry D. | |
dc.creator | Lee, Insung | |
dc.date.accessioned | 2024-02-09T20:48:36Z | |
dc.date.available | 2024-02-09T20:48:36Z | |
dc.date.issued | 1992 | |
dc.identifier.uri | https://hdl.handle.net/1969.1/DISSERTATIONS-1374767 | |
dc.description | Vita | en |
dc.description | Major subject: Electrical Engineering | en |
dc.description.abstract | Efficient speech coders using tree coding combined with harmonic scaling are designed at the rates of 6.4 kilobits/sec (kbps) and 4.8 kbps. A time domain harmonic scaling algorithm (TDHS) is used to compress input speech by a factor of two. This process allows the tree coder to have 2 bits/sample for 6.4 kbps and 1.5 bits/sample for 4.8 kbps in the case of a 6.4 kHz sampling rate. Various window functions and pitch extraction algorithms are compared in the TDHS algorithm. In the backward adaptive tree coder, there are three components of the code generator, including a hybrid adaptive quantizer, a short-term predictor and a pitch predictor. The short-term predictor with a pole-zero structure improves the performance of the tree coder in the error free channel over an all-pole structure. The robustness of the tree coder is achieved by carefully choosing the input of the short-term predictor adaptation. The residual signal shaped by an all-zero filter is used as the input for adaptation. The all-zero filter is obtained by truncating the infinite impulse response of the pole-zero synthesis filter. Another method to improve the robustness of the tree coder is the inclusion of a smoother in the pitch predictor. The coefficients of the smoother with three taps are computed from the estimated autocorrelation function of the pitch synthesizer output. The inclusion of a smoother provides a small improvement in the error free channel and robustness to transmission errors. Subjectively, tree coding combined with TDHS achieves very good quality speech at the rate of 6.4 kbps and good quality speech at 4.8 kbps. The performance of the coding system is evaluated for real speech by means of signal-to-noise ratio (SNR), segmental SNR, frequency domain SNR, spectrograms, and informal listening tests. | en |
dc.format.extent | xv, 148 leaves | en |
dc.format.medium | electronic | en |
dc.format.mimetype | application/pdf | |
dc.language.iso | eng | |
dc.rights | This thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use. | en |
dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | |
dc.subject | Major electrical engineering | en |
dc.subject.classification | 1992 Thesis L4783 | |
dc.subject.lcsh | Speech processing systems | en |
dc.subject.lcsh | Signal processing | en |
dc.subject.lcsh | Digital techniques | en |
dc.subject.lcsh | Coding theory | en |
dc.title | Robust tree coding combined with harmonic scaling of speech | en |
dc.type | Thesis | en |
thesis.degree.discipline | Electrical Engineering | en |
thesis.degree.grantor | Texas A&M University | en |
thesis.degree.name | Doctor of Philosophy | en |
thesis.degree.name | Ph. D | en |
thesis.degree.level | Doctorial | en |
dc.contributor.committeeMember | Georghiades, Costas N. | |
dc.contributor.committeeMember | Griswold, Norman C. | |
dc.contributor.committeeMember | Hsing, Tailen | |
dc.type.genre | dissertations | en |
dc.type.material | text | en |
dc.format.digitalOrigin | reformatted digital | en |
dc.publisher.digital | Texas A&M University. Libraries | |
dc.identifier.oclc | 30130138 |
Files in this item
This item appears in the following Collection(s)
-
Digitized Theses and Dissertations (1922–2004)
Texas A&M University Theses and Dissertations (1922–2004)
Request Open Access
This item and its contents are restricted. If this is your thesis or dissertation, you can make it open-access. This will allow all visitors to view the contents of the thesis.