Method and apparatus for estimating random jitter (RJ) and deterministic jitter (DJ) from bit error rate (BER)
First Claim
1. A method, comprising:
- obtaining a plurality of error rates corresponding to a plurality of sampling clock offset values;
transforming the plurality of error rates to obtain a plurality of transformed error rates;
forming a linear relationship between the plurality of transformed error rates and the plurality of sampling clock offset values;
obtaining a deterministic jitter value from the linear relationship; and
obtaining a random jitter value from the linear relationship.
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Abstract
An apparatus and method provides prediction of BER for an interface between ICs, such as a processor and a memory device, without using special test equipment. A known data pattern or PRBS is transmitted to a receiver, which compares the received data values with expected data values to determine if a bit error has occurred in an embodiment of the present invention. A center of data eye and the edge of the data eye are sampled (over sampled) in order to determine if a bit error has occurred in an alternate embodiment of the present invention. A first counter is used to count the total number of bits sampled and the second counter is used to count the number of errors that occurred in the total number of bits sampled.
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Citations
45 Claims
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1. A method, comprising:
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obtaining a plurality of error rates corresponding to a plurality of sampling clock offset values; transforming the plurality of error rates to obtain a plurality of transformed error rates; forming a linear relationship between the plurality of transformed error rates and the plurality of sampling clock offset values; obtaining a deterministic jitter value from the linear relationship; and obtaining a random jitter value from the linear relationship. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method, comprising:
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adjusting a sampling signal by a first plurality of offset values; counting a plurality of data values to obtain a total number of data values for respective offset values in the first plurality of offset values; counting a number of errors in the plurality of data values for respective offset values in the first plurality of offset values; calculating a first plurality of error rates in response to the total number of data values in the plurality of data values and the number of errors in the plurality of data values for respective offset values in the first plurality of offset values; adjusting the sampling signal by a second plurality of offset values; counting a plurality of data values to obtain a total number of data values for respective offset values in the second plurality of offset values; counting a number of errors in the plurality of data values for respective offset values in the second plurality of offset values; calculating a second plurality of error rates in response to the total number of data values in the plurality of data values and the number of errors in the plurality of data values for respective offset values in the second plurality of offset values; transforming the first and second plurality of error rates to obtain a first and second plurality of transformed error rates; forming a first and second linear relationship between the first and second plurality of transformed error rates and the first and second plurality of offset values, respectively; obtaining a deterministic jitter value from the first and second linear relationship; and obtaining a random jitter value from the first and second linear relationship. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. An apparatus, comprising:
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a receiver to sample a plurality of data values in response to a plurality of sampling clock offset values;
wherein the receiver includes;a first counter to indicate a number of data values received by the receiver, a second counter to indicate a number of errors in the number of data values, and a processing device, coupled to the receiver;
wherein the processing device;obtains a plurality of error rates corresponding to the plurality of sampling clock offset values, wherein a first error rate in the plurality of error rates is calculated in response to the number of data values and the number of errors, transforms the plurality of error rates to obtain a plurality of transformed error rates, forms a linear relationship between the plurality of transformed error rates and the plurality of sampling clock offset values, obtains a deterministic jitter value from the linear relationship, and obtains a random jitter value from the linear relationship. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. An apparatus, comprising:
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an integrated circuit that operates in a first and second mode of operation, wherein the first mode of operation a receiver samples a plurality of data values in response to a first plurality of sampling clock offset values, wherein the second mode of operation a transmitter generates a plurality of data values in response to a second plurality of sampling clock offset values, a first counter to indicate a number of data values received by the receiver, a second counter to indicate a number of errors in the number of data values, and a processing device, coupled to the integrated circuit;
wherein the processing device;obtains a plurality of error rates corresponding to either the first or second plurality of sampling clock offset values, wherein a first error rate in the plurality of error rates is calculated in response to the number of data values and the number of errors, transforms the plurality of error rates to obtain a plurality of transformed error rates, forms a linear relationship between the plurality of transformed error rates and either the first or second plurality of sampling clock offset values, obtains a deterministic jitter value from the linear relationship, and obtains a random jitter value from the linear relationship.
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43. An apparatus, comprising:
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an integrated circuit memory device including, a transmitter to generate a plurality of data values, a receiver to receive the plurality of data values, a first counter to indicate a number of data values received by the receiver, a second counter to indicate a number of errors in the number of data values, and a processing device, coupled to the integrated circuit memory device;
wherein the processing device;obtains a plurality of error rates corresponding to a plurality of sampling clock offset values, wherein a first error rate in the plurality of error rates is calculated in response to the number of data values and the number of errors, transforms the plurality of error rates to obtain a plurality of transformed error rates, forms a linear relationship between the plurality of transformed error rates and the plurality of sampling clock offset values, obtains a deterministic jitter value from the linear relationship, and obtains a random jitter value from the linear relationship.
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44. An apparatus, comprising:
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a receiver to receive a plurality of data values in response to a sample clock signal; and
,means, coupled to the receiver, for providing a deterministic jitter value and a random jitter value based on a linear relationship between a plurality of bit error rates and corresponding sample clock offset values.
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45. An apparatus, comprising:
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a receiver capable to receive a plurality of data values in response to a sample clock signal; and
,means, coupled to the receiver, for calculating a plurality of bit error rate values corresponding to a plurality of sample clock offset in either the transmitter or receiver, or both.
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Specification