PURPOSE: To attach desired stretching feeling on a stereo signal, by outputting the quantity of phase shift by a phase shifter increasingly as a frequency band area increases higher, and outputting a signal in another path without applying the phase shift at every frequency band area, in a device in which a monoral signal is made into stereo.
CONSTITUTION: The outputs of band-pass dividing filters 1∼3 are branched into two outputs, and one of them is added and synthesized on an adder 20 as it is, and is converted to an analog output at a D/A converter 32. The other one is inputted to the phase shifters 11∼13, then, the phase shift is applied. In other words, the phase shift is scarcely applied on the output of the band-pass dividing filter 1 at the phase shifter 11, and a cross-correlation function is set nearly at 1, and the quantity of the phase shift for the output of the band-pass dividing filter 3 is increased to 140π with 20kHz at the phase shifter 13, then, the cross-correlation function is approached to 0. And the phase shift for the output of the band-pass dividing filter 2 is applied by 0.5π with 1.0kHz at the phase shifter 12, and the cross-correlation function is set nearly at 0.3π, and those are added and synthesized at an adder 21, and the stereo signal can be obtained with the output of the D/A converter 32.
UMIGAMI SHIGEYUKI
FUJIMOTO SHOJI
FUJITSU TEN LTD