The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 19, 1999
Filed:
May. 16, 1997
Michael L Petroff, West Hills, CA (US);
Harman Motive, Inc., Martinsville, IN (US);
Abstract
A stereophonic signal processing system provides optimal spatial enhancement in a compact stereo sound system having limited physical separation between two relatively small stereo loudspeakers with accordingly limited low-frequency output capability. A difference signal is derived from the left and right stereo signals by subtraction in a a differential amplifier circuit, which may be made frequency-dependent so that the rejection of correlated information decreases with increasing frequency. The difference signal is processed through a frequency equalizer circuit, and an inverted version is derived via an inverter; the non-inverted and inverted difference signals are filtered according to a high-pass filter function having an upper-bass cutoff frequency selected to avoid excessive spatialization at low frequencies. The left and right stereo signals are filtered according to a transfer function having low-bass cutoff frequency selected to minimize reproduction distortion by minimizing low frequency signal components below an effective frequency range of the loudspeakers. The filtered stereo signals are separately mixed in optimal proportion with the equalized and filtered difference signals, thereby providing optimal spatial enhancement for small and closely-spaced stereo loudspeakers.