Linear predictive coding technique with interleaved sequence digital lattice filter
US4695970A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1984 |
| Grant date | Sep 22, 1987 |
| Priority date | — |
| Expiry date | Aug 31, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/06
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An LPC digital lattice filter includes a full adder (44) which has one input thereof multiplexed with a multiplexer (46) and the other input thereof multiplexed by a multiplexer (50). Combination of the multiplication and addition steps with the full adder (44) results in the calculation of one of the digital filter equations. The result of each of these equations is either a Y-value or a B-value. The Y-values are stored in the output of a Y-register (78) and the B-values are stored in a nine stage B-stack (100) for delay thereof. The multiplexer (60) selects multiplicands from either the output of the one stage delay (86), from the B-stack (100) or the input excitation I. The multiplexer (46) selects addends from either the output of the B-stack (100), the output of the B-register (96) or from the multiplexers (60) or (66). The values are calculated in an interleaved sequence with a Y-value calculated and then a B-value calculated utilizing this generated Y-value. This generated Y-value is then used in calculating the next sequential Y-value and then discarded. However, the B-values are delayed until calculation of the next set of equations. The interleaved sequence allows use of …
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