High speed decision feedback equalizer
AssigneeTexas Instruments Incorporated
InventorsBhavesh G. Bhakta, Sridhar Ramaswamy, Robert F. Payne, Song Wu
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Abstract
An equalizer comprises a sampler, a filter, and a summer. The sampler samples a signal indicative of an input communication signal to determine digital decision output signals having a communication device data rate. The filter receives digital decision output signals from the sampler and generates equalization signals therefrom. The summer couples to the sampler and the filter and combines together the input communication signal with the equalization signals. Further, a plurality of clocks control timing associated with the sampler. These clocks have frequencies that are less than the predetermined data rate of the digital decision output signals.
Claims23
An equalizer for use in a communication device, comprising:
- a sampler that samples a signal indicative of an input communication signal to determine digital decision output signals having a predetermined data rate;
- a filter that receives digital decision output signals from said sampler and generates equalization signals therefrom;
- and
- a summer coupled to the sampler and the filter, said summer combines together the input communication signal with the equalization signals;
- wherein a plurality of clocks control timing associated with the sampler, said clocks having frequencies that are less than a data rate of the communication device;
- wherein the equalizer includes a sensitivity test process in which an at-speed sensitivity of the equalizer can be determined, the process includes disabling an input amplifier, providing a predetermined set of tap coefficients to the filter, determining if the sampler generates a repeating pattern associated with the set of tap coefficients, and repeating the sensitivity test process with other predetermined sets of tap coefficients until the sampler no longer determines the repeating pattern associated the set of tap coefficients provided to the filter.
An equalizer, comprising:
- a sampler that samples a signal indicative of an input communication signal to determine digital decision output signals;
- a filter that receives digital decision output signals from said sampler and generates equalization signals therefrom;
- a summer coupled to the sampler and the filter, said summer combines together the input communication signal with the equalization signals;
- and
- a clock circuit coupled to said filter and said sampler, said clock circuit generates a plurality of inter-symbol interference (“ISI”) cancellation clock signals that operate said filter from a set of quadrature clocks used to operate the sampler;
- wherein the equalizer includes a sensitivity test process in which an at-speed sensitivity of the equalizer can be determined, the process includes disabling an input amplifier, providing a predetermined set of tap coefficients to the filter, determining if the sampler generates a repeating pattern associated with the set of tap coefficients, and repeating the sensitivity test process with other predetermined sets of tap coefficients until the sampler no longer determines the repeating pattern associated the set of tap coefficients provided to the filter.
An equalizer, comprising:
- an input amplifier that receives an input communication signal;
- a sampler that samples a signal indicative of an input communication signal to generate digital decision output signals;
- a filter that receives digital decision output signals from said sampler and generates equalization signals therefrom;
- a summer coupled to the sampler and the filter, said summer combines together the input communication signal with the equalization signals;
- and
- wherein the equalizer includes a sensitivity test process in which an at-speed sensitivity of the equalizer can be determined, the process includes disabling the input amplifier, providing a predetermined set of tap coefficients to the filter, determining if the sampler generates a repeating pattern associated with the set of tap coefficients, and repeating the sensitivity test process with other predetermined sets of tap coefficients until the sampler no longer determines the repeating pattern associated the set of tap coefficients provided to the filter.
Dependencies are inferred from the claim text.