초록 ▼

A transform coder wherein different segments of signal samples to be transmitted to a receiver are encoded using different coding transforms. In order to avoid problems encountered with signal samples forming the transition between successive segments an intermediate transform is used for such trans

A transform coder wherein different segments of signal samples to be transmitted to a receiver are encoded using different coding transforms. In order to avoid problems encountered with signal samples forming the transition between successive segments an intermediate transform is used for such transition. This has conventionally required significant transmission overhead, because the selected intermediate transform matrix must be transmitted to the receiver to enable it to decode the transitional signal samples. The invention instead provides weighting factors to indicate the extent to which frequency spectra of the basis functions of the intermediate transform resemble the frequency spectra of the basis functions of the transforms used for the adjoining signal segments. The inverse of the intermediate transform can then be calculated by the receiver from the weighting factors.

대표청구항 ▼

[ I claim:] [1.] A method of transform coding a signal, comprising the steps of subjecting a first series of samples of the signal to a first lapped transform and a second series of samples of the signal to a second lapped transform, characterized by subjecting signal samples forming the transition

[ I claim:] [1.] A method of transform coding a signal, comprising the steps of subjecting a first series of samples of the signal to a first lapped transform and a second series of samples of the signal to a second lapped transform, characterized by subjecting signal samples forming the transition from the first to the second series of samples to an intermediate transform, said intermediate transform being determined by weighting factors indicating to what extent the frequency spectra of the basis functions of said intermediate transform resemble the frequency spectra of the first and second transform, and accommodating said weighting factors in the encoded signal.