DEVICE, METHOD, AND PROGRAM FOR EXPANDING FREQUENCY BAND

摘要

The present technology relates to a device, method and program for expanding frequency band such that a high quality audio signal can be obtained more simply. A bandpass filter allows various band components of an input signal to pass and outputs a low-frequency sub-band signal and a high-frequency sub-band signal. A high-frequency sub-band power estimating circuit calculates an estimated value for high-frequency sub-band power for each high-frequency sub-band on the basis of characteristic quantities for the input signal. A high-frequency sub-band power comparison circuit compares the estimated value for the high-frequency sub-band power and the high-frequency sub-band power found from the high-frequency sub-band signal for the input signal and sets the higher thereof as pseudo-high-frequency sub-band power. A high-frequency signal generating circuit generates a high-frequency signal on the basis of the pseudo-high-frequency sub-band power and low-frequency sub-band signal. A signal adder adds the low-frequency signal and high-frequency signal and generates an output signal. This technology can be used in devices for expanding frequency band.