Patent ID: 6590983
Filing Date: 2003-07-08
Classification: H04S

Abstract:
A stereo synthesizing apparatus to produce left and right pseudo-stereophonic output signals from a monophonic signal, comprising:a monophonic input configured to receive a monophonic signal; a perspective filter operatively couples to said monophonic input, said perspective filter configured to de-emphasize selected frequency portions of said monophonic signal to produce a first filtered signal; a bandpass filter operative coupled to said monophonic input, said bandpass filter configured to pass frequencies of said monophonic signal containing human voice information; a ninety-degree phase shifter operatively coupled to an output of said bandpass filter to produce a second filtered signal; a left channel mixer adapted to add said first filtered signal to said second filtered signal to produce a left channel output signal; and a right channel mixer adapted to subtract said first filtered signal from said second filtered signal to produce a right channel output signal, wherein the left channel output signal and the right channel output signal have a lower phase difference in a mid band frequency range and a higher phase difference at very high frequencies.