System and Method for Pre and Post-Tap Zeroing
AssigneeApplied Micro Circuits Corporation
InventorJay Quirk
Life of this patent
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Abstract
A system and method are provided for zeroing pre and post-tap settings in a link partner using a plurality of voltage gain taps. The method provides a link partner (LP) transmitter. A network-connected local device (LD) selects an LP pre-tap or post-tap. The LD also chooses a zero gain setting for the selected LP tap. In a first iteration, the LD directs the LP to decrease the difference between the selected tap gain setting and the zero setting by 1 step. If a limit signal is not received by the LD, the LP is directed to maximally increase the center tap gain setting until a limit signal is received. The iterations are continued until a limit signal is returned in response to the LD directing the LP to decrease the difference between the selected tap gain setting and the zero setting.
Claims12
In a link partner using a plurality of voltage gain taps, a method for zeroing pre and post-tap settings, the method comprising:
- providing a link partner (LP) transmitter having a signal input, a plurality of parallel selectable voltage gain taps connected to the signal input, including a non-delayed pre-tap, a center tap with a delay of one unit, and a post-tap with a delay of 2 units, and a network-connected output to supply the sum of the taps;
- a network-connected local device (LD) choosing an LP tap selected from the group consisting of the pre-tap and the post-tap;
- the LD choosing a zero gain setting for the selected LP tap;
- in a first iteration, the LD directing the LP to decrease the difference between the selected tap gain setting and the zero setting by 1 step;
- if a limit signal is not received by the LD, directing the LP to maximally increase the center tap gain setting until a limit signal is received;
- and,
- continuing the iterations until a limit signal is returned in response to the LD directing the LP to decrease the difference between the selected tap gain setting and the zero setting.
A local device (LD) system for zeroing the pre and post-tap settings in a link partner (LP) transmitter using a plurality of voltage gain taps, the system comprising:
- an LD signal quality module having an output to supply a zero setting command for a tap selected from a group consisting of an LP pre-tap and an LP post-tap;
- an LD tap control module having an input to accept the zero setting command and a network interface to supply a sequence of tap modification signals to an LP transmitter having a plurality of parallel selectable voltage gain taps connected to a signal input, including a non-delayed pre-tap, a center tap with a delay of one unit, and a post-tap with a delay of 2 units, and a network-connected output to supply the sum of the taps, the LD tap control module sending a sequence of tap modification signals including directions to:
- in a first iteration, decrease the difference between the selected tap gain setting and the zero setting by 1 step;
- if a limit signal is not received by the LD tap control module, directing the LP to maximally increase the center tap gain setting until a limit signal is received;
- and,
- continuing the iterations until a limit signal is returned in response to the LD tap control module directing the LP to decrease the difference between the selected tap gain setting and the zero setting.
Dependencies are inferred from the claim text.