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Patent Searching and Data


Title:
RINGING ELIMINATION DEVICE
Document Type and Number:
Japanese Patent JPH03173276
Kind Code:
A
Abstract:

PURPOSE: To prevent deterioration in the resolution without attenuating a high frequency signal different from a conventional device by adopting the method selecting a filter whose amplitude frequency characteristic is unchanged for eliminating ringing.

CONSTITUTION: A reception reference waveform signal yj is extracted from a reception signal by a gate circuit 30. The obtained signal yj is stored in a memory 31. On the other hand, a reference waveform signal xj is stored in a memory 32 in advance. An impulse response coefficient hj is obtained from the obtained signals yj, xj at a polynomial divider 33 by using equation. The obtained coefficient hj is processed to be a symmetrical coefficient as (hj+hL-j)/2 at a symmetry processing computing element 34. Moreover, a front ringing portion of the impulse response of the symmetrical coefficient filter is expanded to point-symmetry with respect to the center of the response to obtain a point- symmetry coefficient by using a point symmetry processing computing element 35. The obtained symmetry coefficient and point-symmetry coefficient are given to a symmetry coefficient filter 21 and a point-symmetry coefficient filter 22 to build up a ringing elimination device with the same coefficient as a transfer function of the transmission line at a receiver side.


Inventors:
ONISHI MAKOTO
IZAWA YUJI
Application Number:
JP31062489A
Publication Date:
July 26, 1991
Filing Date:
December 01, 1989
Export Citation:
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Assignee:
HITACHI LTD
International Classes:
G06T5/20; H03H17/02; H03H17/06; H03H21/00; H04N5/21; (IPC1-7): G06F15/68; H03H17/02; H03H17/06; H04N5/21
Attorney, Agent or Firm:
Katsuo Ogawa (1 person outside)