Cheng Chung Shih

US Patent:

52491838, Sep 28, 1993

Filed:

Mar 14, 1991

Appl. No.:

7/669501

Inventors:

Dave Wong - Mountain View CA
Haim Shafir - Sacramento CA
Joe Heideman - Orangevale CA
Cheng C. Shih - Rancho Cordova CA

Assignee:

Level One Communications, Inc. - Folsom CA

International Classification:

H04L 1240

US Classification:

370 853

Abstract:

A local area network (LAN) having a 10Base-T media attachment unit (MAU) is disclosed for coupling an attachment unit interface (AUI) to a twisted pair link through an AUI port of the 10Base-T MAU. In addition to meeting or exceeding standards set forth in the proposed supplement (P802. 3I/D10) to IEEE standard 802. 3 for LANs, the MAU provides an interface between the AUI and a RJ45 (twisted pair) connector which auto-engages when activity is detected on the twisted pair link. Lack of activity on the twisted pair link forces the 10Base-T MAU to isolate its AUI port from the AUI. An Ethernet (coaxial) type MAU commonly connected with the 10Base-T MAU at the AUI may be utilized without manual intervention when the twisted pair link is inactive.

US Patent:

51666359, Nov 24, 1992

Filed:

Mar 27, 1991

Appl. No.:

7/675648

Inventors:

Cheng C. Shih - Rancho Cordova CA

Assignee:

Level One Communications, Inc. - Folsom CA

International Classification:

H03F 345

US Classification:

330253

Abstract:

A cost-effective, low power and low distortion digital data line driver is disclosed with the capability to operate from a limited voltage source while maintaining wide output voltage swings. The line driver has the noise immunity attribute of a fully differential input device without all the usual complex CMFB circuitry normally required. The line driver provides a low distortion output with a low output impedance and maintains its impedance value on the same order of magnitude at frequencies up to four times the Nyquist rate.

US Patent:

50577948, Oct 15, 1991

Filed:

Feb 26, 1991

Appl. No.:

7/661496

Inventors:

Cheng C. Shih - Rancho Cordova CA

Assignee:

Level One Communications, Inc. - Folsom CA

International Classification:

H03L 7089

US Classification:

331 1A

Abstract:

An all-digital phase-locked loop (ADPLL) is disclosed having a wide bandwidth while maintaining relatively small steps for phase error correction. A random walk filter with memory and a pattern sensitive phase adjustment circuit cooperate to control the ADPLL frequency/phase adjustment rate by taking multiple, relatively smnall steps in phase error correction at fixed intervals of time. A short cycle occurs when the phase disparity is large, interrupting the execution of the fixed interval cycle expediting the ADPLL phase lock time without sacrificing resolution in the phase error correction steps.