High efficiency encoding device and a noise spectrum modifying device and method
US5563913A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1993 |
| Grant date | Oct 8, 1996 |
| Priority date | — |
| Expiry date | Oct 28, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/665
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
An apparatus and method for processing an input digital signal in which an input digital audio signal at an input terminal 11 is supplied via a one-block delay unit 17 to a difference unit 20, an output of which is processed by noise-shaping circuit 21 and restored by a near-instantaneous compressor 26, a near-instantaneous expander 27 and an accumulator 28 so as to be fed back to the difference unit 20 to find a difference between a signal of a directly preceding sample and a signal of the current sample. The noise shaping circuit 21 modifies the spectrum of the quantization noise by taking aural characteristics, such as equal-loudness characteristics or masking characteristics, into account for diminishing the level of the quantization noise as perceived by the ear. The noise level as perceived may be reduced in a manner desirable for the sound quality without changing the existing format.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.