Cisco Technology, Inc.

Nan Tu

Charles J Naegeli

Guenter E Roeck

Mark E Millet

Nozar Azarakhsh

Harihara Mahesh

Chrisanto De Jesus Leano

Joseph C H Fung

Yuzon Hao

Hungsan Chen

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.

Technique for determining carrier-to-noise ratio of selected channels in an access network

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.

Method and apparatus for a router line card with adaptive selectable gain control

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San Jose, CA, United States of America

Nan Tu