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:
Feb. 04, 2003
Filed:
Oct. 25, 2000
Hirohisa Tasaki, Tokyo, JP;
Bunkei Matsuoka, Tokyo, JP;
Ikuo Kajiyama, Tokyo, JP;
Shinya Takahashi, Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A first pseudo-echo signal approximating an echo of a reception signal superposed on a transmission signal is produced from a delayed reception signal corresponding to a past time according to filer coefficients, and a first residual signal is produced from the first pseudo-echo signal and a delayed transmission signal. Also, the filer coefficients are renewed to reduce the first residual signal. Therefore, when a single-talk state based on a far-end caller's voice of the reception signal is changed to a double-talk state by adding a near-end caller' voice to the transmission signal, the first filter coefficients deteriorate. Also, a second pseudo-echo signal is produced from a reception signal currently received according to the first filter coefficients renewed. Because a time difference exists between the signals corresponding to the renewal of the first filter coefficients and the production of the second pseudo-echo signal, a deterioration factor is indicated in a delayed second residual signal produced from the second pseudo-echo signal, so that the double-talk state can be detected according to a difference between the first residual signal and the delayed second residual signal.