Nan Tu

US Patent:

6757522, Jun 29, 2004

Filed:

Dec 11, 2000

Appl. No.:

09/735200

Inventors:

Charles Naegeli - Half Moon Bay CA
Hungsan Chen - San Jose CA
Nan Tu - San Jose CA
Harihara Mahesh - San Jose CA
Chrisanto de Jesus Leano - San Jose CA
Nozar Azarakhsh - Modesto CA

Assignee:

Cisco Technology, Inc. - San Jose CA

International Classification:

H04B 1700

US Classification:

455 6711, 455423, 725107

Abstract:

A technique is disclosed for determining a carrier-to-noise ratio (CNR) value for a selected channel of an access network. A background noise level on the selected channel is measured during a first time interval during which none of the network nodes are transmitting signals on the selected channel. A first signal strength on the selected channel is also measured during a second time interval during which a first network node is transmitting at least one signal on the selected channel. A CNR value for the selected channel may then be calculated using the measured background noise level information and the measured first signal strength information. According to a specific implementation, the calculation of the CNR value for the selected channel is not based upon an Error Vector Magnitude value associated with the signal transmitted from the first network node.

US Patent:

62859609, Sep 4, 2001

Filed:

Oct 7, 1998

Appl. No.:

9/167775

Inventors:

Joseph C. H. Fung - San Jose CA
Mark E. Millet - Mountain View CA
Charles J. Naegeli - Montara CA
Nan Tu - San Jose CA
Guenter Roeck - San Jose CA
Yuzon Hao - San Jose CA

Assignee:

Cisco Technology, Inc. - San Jose CA

International Classification:

H04M 124

US Classification:

702107

Abstract:

A system and method are disclosed for calibrating a line card having a gain control circuit and memory device. The gain control circuit is configured to receive an input signal and an adjustment signal and to output an adjusted output signal that is based on the input signal and the adjustment signal. The gain control circuit also is configured to alter the adjustment signal to a nominal adjustment value so that an adjusted amplitude value of the adjusted signal converges with a nominal amplitude value. A first input signal, a first adjustment signal, and a nominal amplitude value are provided to the gain control circuit. A first nominal adjustment value is determined. The first nominal adjustment value is substantially permanently stored within a first address of the memory device with the first address being associated with the first input signal.