Patent ID: 6785391
Filing Date: 2004-08-31
Classification: H04S

Abstract:
A transfer characteristic measuring apparatus for simultaneously measuring transfer characteristics of NÃ—M transmission paths of a linear FIR system defined between its N input points and M output points, said N and M being an integer equal to or greater than 2 and an integer equal to or greater than 1, respectively, said apparatus comprising:N pre-filters having transfer characteristics of different zeros, for processing N-channel signals input thereinto and for outputting preprocessed signals, respectively; N actuators for inputting said preprocessed signals from said N pre-filters to said N input points of said linear FIR system, respectively; M sensors for detecting response signals from said linear FIR system at said M output points; and a transfer characteristic estimation part for calculating the transfer characteristics of said NÃ—M transmission paths from said preprocessed signals output from said N pre-filters and said response signals detected by said M sensors; wherein said transfer characteristic estimation part includes: M N-input single-output adaptive filters supplied with said preprocessed signals from said N pre-filters, for outputting replica signals that are estimated versions of said response signals from said linear FIR system; and M subtractors supplied with said M replica signals and said M response signals from said linear FIR system, for detecting their differences and generating error signals corresponding thereto and for applying said M error signals to said M adaptive filters corresponding to said M subtractors, respectively, and wherein said M adaptive filters include means for adaptively updating filter coefficients representative of their transfer characteristics so that said error signals are minimized to thereby obtain said updated filter coefficients as impulse responses indicative of the transfer characteristics of said linear FIR system.