公开(公告)号：DE69225709D1

公开(公告)日：1998-07-02

申请号：DE69225709

申请日：1992-10-15

Applicant: IBM

Inventor： CHERUBINI GIOVANNI DR ,  OELCER SEDAT DR ,  UNGERBOECK GOTTFRIED DR

IPC: H04B3/14

Abstract: Adaptive analog equalizer permitting 16 Mbit/s token ring (TR) transmission over unshielded twisted-pair (UTP) cables. The equalizer (29) is located at the wiring concentrator (25), and consists of a variable and a fixed filter section. The existing TR receiver (49) and transmitter (53) remain unchanged. To compensate for distortion introduced by the cable section (19b) preceding the equalizer, the level of the signal (B) at the equalizer output (35) is used as a control criterion. The additional distortion contributed by the cable section (21a) following the equalizer is accounted for by measuring the level of the signal (D) received from the transmitter (53) of the next TR station. By these two measurements, the equalizer is adjusted such that the cable-length dependent distortion is eliminated at the next receiver (49). Transmitted Manchester-coded signals are received essentially distortion-free for cable attenuation ranging between 0 and 25 dB at 16 MHz, corresponding to zero and maximum cable lengths between TR stations. The amplification provided by equalization at the concentrator significantly mitigates also the effect of near-end crosstalk from the transmitter into the receiver input of TR stations.

公开(公告)号：DE3852395T2

公开(公告)日：1995-05-24

申请号：DE3852395

申请日：1988-10-17

Applicant: IBM

Inventor： DOLIVO FRANCOIS B DR ,  OELCER SEDAT DR ,  RUENGELER ANDREAS DR ,  SCHOTT WOLFGANG HANS DR

IPC: G11B5/035 ,  G11B20/10 ,  G11B20/18 ,  H03H15/00 ,  H03H17/00 ,  H03H21/00 ,  H04B3/04 ,  H04L25/03 ,  H04L27/01

Abstract: The channel characteristics of magnetic-disk storage devices vary with track radius. An adaptive 3-tap transversal equalizer that compensates these variations for systems using partial-response signaling is presented. The equalizer coefficients are updated by applying a procedure that is related to the recursive least-squares algorithm. This new updating procedure does not require multiplications and is well suited for high-speed implementation. Results obtained by computer simulations and measurements with a prototype have shown that the proposed adaptive equalizer can effectively compensate variations in magnetic-disk channel characteristics with track radius.

公开(公告)号：DE3852395D1

公开(公告)日：1995-01-19

申请号：DE3852395

申请日：1988-10-17

Applicant: IBM

Inventor： DOLIVO FRANCOIS B DR ,  OELCER SEDAT DR ,  RUENGELER ANDREAS DR ,  SCHOTT WOLFGANG HANS DR

IPC: G11B5/035 ,  G11B20/10 ,  G11B20/18 ,  H03H15/00 ,  H03H17/00 ,  H03H21/00 ,  H04B3/04 ,  H04L25/03 ,  H04L27/01

Abstract: The channel characteristics of magnetic-disk storage devices vary with track radius. An adaptive 3-tap transversal equalizer that compensates these variations for systems using partial-response signaling is presented. The equalizer coefficients are updated by applying a procedure that is related to the recursive least-squares algorithm. This new updating procedure does not require multiplications and is well suited for high-speed implementation. Results obtained by computer simulations and measurements with a prototype have shown that the proposed adaptive equalizer can effectively compensate variations in magnetic-disk channel characteristics with track radius.