Pulse or digital communications – Equalizers – Automatic
Reexamination Certificate
2007-07-10
2007-07-10
Ghebretinsae, Temesghen (Department: 2611)
Pulse or digital communications
Equalizers
Automatic
C708S323000
Reexamination Certificate
active
10112869
ABSTRACT:
The present invention proposes a new method and apparatus for the improvement of digital filterbanks, by a complex extension of cosine modulated digital filterbanks. The invention employs complex-exponential modulation of a low-pass prototype filter and a new method for optimizing the characteristics of this filter. The invention substantially reduces artifacts due to aliasing emerging from independent modifications of subband signals, for example when using a filterbank as an spectral equalizer. The invention is preferably implemented in software, running on a standard PC or a digital signal processor (DSP), but can also be hardcoded on a custom chip. The invention offers essential improvements for various types of digital equalizers, adaptive filters, multiband companders and spectral envelope adjusting filterbanks used in high frequency reconstruction (HFR) systems.
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Coding Technologies AB
Ghebretinsae Temesghen
Glenn Michael A.
Glenn Patent Group
Torres Juan Alberto
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