Digital signal processing

摘要

In processing a digital information signal (a digital video signal etc), an improvement in the accuracy of the signal process can be made by integrating the time region process and the frequency region process. In one embodiment, an input digital video signal is supplied to a DCT circuit 3. The DCT circuit 3 converts the input video digital signal into coefficient data. A categorizing circuit 5 separates a flat component 6a and an impulse component 6b in a frequency region from the input signal. The flat component 6a is supplied to an inverse DCT circuit 7. The inverse DCT circuit 7 converts the input signal into a signal on a time axis. A class categorizing adaptive processing circuit 9 compensates a resolution in a time region. The impulse component 6a is supplied to a gain converting circuit 10. The gain converting circuit 10 compensates the high band in a frequency region. The output signal of the gain converting circuit 10 is supplied to an inverse DCT circuit 11. The inverse DCT circuit 11 converts the input signal into a signal on a time axis. A mix circuit 14 mixes signals that have been processed. Thus, a video signal compensated the resolution is obtained from an output terminal 15. The adaptive procession circuit 9 and the gain converting circuit 10 use pre-learnt predicted coefficients, predicted values, and gain converting ratio.