SE323721B - - Google Patents
Info
- Publication number
- SE323721B SE323721B SE4042/66A SE404266A SE323721B SE 323721 B SE323721 B SE 323721B SE 4042/66 A SE4042/66 A SE 4042/66A SE 404266 A SE404266 A SE 404266A SE 323721 B SE323721 B SE 323721B
- Authority
- SE
- Sweden
- Prior art keywords
- channel
- unvoiced
- voiced
- pass filter
- integrator circuit
- Prior art date
Links
- 238000001228 spectrum Methods 0.000 abstract 2
- 238000010183 spectrum analysis Methods 0.000 abstract 2
- 239000003990 capacitor Substances 0.000 abstract 1
- 230000010354 integration Effects 0.000 abstract 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
- G10L19/02—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 spectral analysis, e.g. transform vocoders or subband vocoders
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Audiology, Speech & Language Pathology (AREA)
- Computational Linguistics (AREA)
- Signal Processing (AREA)
- Health & Medical Sciences (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Human Computer Interaction (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Compression, Expansion, Code Conversion, And Decoders (AREA)
- Filters That Use Time-Delay Elements (AREA)
- Meter Arrangements (AREA)
- Machine Translation (AREA)
Abstract
1,073,203. Vocoders. INTERNATIONAL BUSINESS MACHINES CORPORATION. Match 15,1966 [March 25, 1965], No. 11188/66. Heading H4R. Channel. vocoder in which each spectrum analysis channel includes a band-pass filter, a rectifier, and a low-pass filter, or integrator circuit; has a voiced-unvoiced detector the output from which is used to lower the cut-off frequency of the low-pass filter, or increase the integration time of the integrator circuit, when unvoiced sounds are detected; in order to reduce noise in the channels. The voiced-unvoiced detector may cause switching between two alternative filters provided for each channel, Fig. 2 (not shown), or it may modify the filtercircuit, e.g. by operation of switch Si. in the filter of Fig. 3. A typical integrator circuit which might be used in each spectrum analysis channel is shown in Fig. 5 in which the spectrum channel signal is applied to band causes capacitor C to be discharged by an amount proportional to the current applied through R 1' Periodically a signal is applied to line a to cause TR 2 to conduct to charge C up to the supply potential. The charging current, which will depend on the total discharge of C since the last charging pulse, flowing through R3 will produce an output pulse on Ki<SP>1</SP> the amplitude of which is proportional to the integral of the spectrum channel signal over a time equal to the period of the pulse signal applied to line a. The voiced-unvoiced discriminator output is employed to increase the period between the pulses applied to line b during unvoiced sounds.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT275665A AT251656B (en) | 1965-03-25 | 1965-03-25 | Processes and arrangements for improving the speech quality in vocoder systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| SE323721B true SE323721B (en) | 1970-05-11 |
Family
ID=3539787
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| SE4042/66A SE323721B (en) | 1965-03-25 | 1966-03-25 |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US3431355A (en) |
| AT (1) | AT251656B (en) |
| BE (1) | BE677136A (en) |
| CH (1) | CH443413A (en) |
| DE (1) | DE1276740B (en) |
| ES (1) | ES324621A1 (en) |
| FR (1) | FR1471628A (en) |
| GB (1) | GB1073203A (en) |
| NL (1) | NL146672B (en) |
| SE (1) | SE323721B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IL84948A0 (en) * | 1987-12-25 | 1988-06-30 | D S P Group Israel Ltd | Noise reduction system |
| DE69317802T2 (en) * | 1992-01-21 | 1998-10-22 | Koninkl Philips Electronics Nv | Method and device for sound enhancement using encapsulation of multiband pass filtered signals in comb filters |
| US5768473A (en) * | 1995-01-30 | 1998-06-16 | Noise Cancellation Technologies, Inc. | Adaptive speech filter |
| US6108610A (en) * | 1998-10-13 | 2000-08-22 | Noise Cancellation Technologies, Inc. | Method and system for updating noise estimates during pauses in an information signal |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3012098A (en) * | 1941-11-22 | 1961-12-05 | Bell Telephone Labor Inc | Telephone privacy |
| US2810787A (en) * | 1952-05-22 | 1957-10-22 | Itt | Compressed frequency communication system |
| US3102928A (en) * | 1960-12-23 | 1963-09-03 | Bell Telephone Labor Inc | Vocoder excitation generator |
| US3261916A (en) * | 1962-11-16 | 1966-07-19 | Ibm | Adjustable recognition system |
-
1965
- 1965-03-25 AT AT275665A patent/AT251656B/en active
- 1965-04-05 US US445563A patent/US3431355A/en not_active Expired - Lifetime
-
1966
- 1966-02-28 BE BE677136D patent/BE677136A/en unknown
- 1966-03-07 CH CH323466A patent/CH443413A/en unknown
- 1966-03-08 NL NL666602974A patent/NL146672B/en unknown
- 1966-03-11 DE DEJ30298A patent/DE1276740B/en not_active Withdrawn
- 1966-03-15 GB GB11188/66A patent/GB1073203A/en not_active Expired
- 1966-03-17 FR FR53804A patent/FR1471628A/en not_active Expired
- 1966-03-24 ES ES0324621A patent/ES324621A1/en not_active Expired
- 1966-03-25 SE SE4042/66A patent/SE323721B/xx unknown
Also Published As
| Publication number | Publication date |
|---|---|
| ES324621A1 (en) | 1967-02-01 |
| AT251656B (en) | 1967-01-10 |
| US3431355A (en) | 1969-03-04 |
| NL146672B (en) | 1975-07-15 |
| NL6602974A (en) | 1966-09-26 |
| CH443413A (en) | 1967-09-15 |
| BE677136A (en) | 1966-07-18 |
| DE1276740B (en) | 1968-09-05 |
| FR1471628A (en) | 1967-03-03 |
| GB1073203A (en) | 1967-06-21 |
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