Abstract: This application discloses a computing system configured to identify a channel in an electronic device is configured to transmit signals encoding data with more than two value levels in response to a correlated test input. The computing system can determine probabilities of value level changes in the transmitted signals based on an encoding for the correlated test input, and measure a step response of the channel. The computing system can perform statistical simulation or analysis on the channel based, at least in part, on the step response of the channel and the determined probabilities of value level changes in the transmitted signals, which can predict a signal integrity of the channel configured to transmit the signals based, at least in part, on the determined probabilities of value level changes in the transmitted signals.

Abstract: This application discloses a computing system configured to identify that a test input for a channel in an electronic device conforms to protocol having a correlated bit pattern. The computing system can determine transition probabilities for bits in the test input based on the protocol having the correlated bit pattern, and measure a step response of the channel. The computing system can perform statistical simulation or analysis on the channel based, at least in part, on the step response of the channel and the transition probabilities for bits in the test input, which can predict a signal integrity of the channel. The computing system can generate an eye diagram or a develop a bit error rate corresponding to the signal integrity of the channel.

Abstract: This application discloses a computing system to perform a fast evaluation of a worst case eye diagram for a channel capable of communicating signals encoding data in more than two value levels. The computing system can identify multiple step responses of the channel, each corresponding to a transition between a plurality of the value levels. The computing system can determine distribution boundaries of the signals at each of the value levels based, at least in part, on the step responses of the channel. The computing system can utilize the distribution boundaries at the value levels to determine boundaries of eye openings between adjacent value levels or to build worst case input patterns used to generate the worst case eye diagram for the channel. The computing system can predict a signal integrity of the channel based on the distribution boundaries at each of the value levels.

Abstract: This application discloses a computing system to perform a fast evaluation of a worst case eye diagram for a channel capable of communicating signals encoding data in more than two value levels. The computing system can identify multiple step responses of the channel, each corresponding to a transition between a plurality of the value levels. The computing system can determine distribution boundaries of the signals at each of the value levels based, at least in part, on the step responses of the channel. The computing system can utilize the distribution boundaries at the value levels to determine boundaries of eye openings between adjacent value levels or to build worst case input patterns used to generate the worst case eye diagram for the channel. The computing system can predict a signal integrity of the channel based on the distribution boundaries at each of the value levels.

Abstract: This application discloses a computing system configured to identify a channel in an electronic device is configured to transmit signals encoding data with more than two value levels in response to a correlated test input. The computing system can determine probabilities of value level changes in the transmitted signals based on an encoding for the correlated test input, and measure a step response of the channel. The computing system can perform statistical simulation or analysis on the channel based, at least in part, on the step response of the channel and the determined probabilities of value level changes in the transmitted signals, which can predict a signal integrity of the channel configured to transmit the signals based, at least in part, on the determined probabilities of value level changes in the transmitted signals.

Abstract: Various implementations of the invention provide methods and apparatuses for generating a test sequence for a driver and channel combination, wherein the driver is non-linear. In various implementations of the invention, a test sequence is generated that produces the worst or near worst error rate of the channel. With various implementations of the invention, voltage waves at the driver and impulse response waves of the channel are generated. In various implementations of the invention, the driver voltage waves and impulse response waves are simulated responses of the driver and channel to a digital signal input. With further implementations of the invention, receiver voltage waves are generated by combining the impulse response wave and the driver voltage waves. Subsequently, a test sequence is selected based upon the combined receiver voltage wave.

Abstract: This application discloses a computing system configured to identify that a test input for a channel in an electronic device conforms to protocol having a correlated bit pattern. The computing system can determine transition probabilities for bits in the test input based on the protocol having the correlated bit pattern, and measure a step response of the channel. The computing system can perform statistical simulation or analysis on the channel based, at least in part, on the step response of the channel and the transition probabilities for bits in the test input, which can predict a signal integrity of the channel. The computing system can generate an eye diagram or a develop a bit error rate corresponding to the signal integrity of the channel.

Abstract: Disclosed herein are exemplary methods, apparatus, and systems for generating test sequences that can be used to evaluate high-speed circuit pathways. The disclosed methods, apparatus, and systems can be used, for example, in a printed circuit board or integrated circuit design flow to analyze signal integrity or other electrical behavior. For example, in one exemplary embodiment, a sequence of code words to be input on a circuit channel is determined in a nonrandom manner. In this embodiment, the sequence of code words complies with a transmission code (for example, the 8b10b transmission code) and is designed to cause the output voltage of the channel to be reduced during a time period in which the channel outputs a logic high value.

Abstract: Techniques for extracting the characteristic response of a non-linear channel are presented. In various implementations of the invention, a channel's characteristic response may be determined by identifying a first input sequence, determining the ones compliment of the first input sequence and then determining the response of the channel to these two input sequences. Subsequently, two input matrices and two response matrices may be generated based upon the two input sequences and their corresponding responses. Given these four matrices, a symmetrical response component may be determined by iteratively solving a system of equations formed from the columns of each matrix. Subsequently, given the symmetric component and these four matrices, an asymmetrical response component may be determined by again iteratively solving the system of equations for the columns of each matrix.

Abstract: Techniques for extracting the characteristic response of a non-linear channel are presented. In various implementations of the invention, a channel's characteristic response may be determined by identifying a first input sequence, determining the ones compliment of the first input sequence and then determining the response of the channel to these two input sequences. Subsequently, two input matrices and two response matrices may be generated based upon the two input sequences and their corresponding responses. Given these four matrices, a symmetrical response component may be determined by iteratively solving a system of equations formed from the columns of each matrix. Subsequently, given the symmetric component and these four matrices, an asymmetrical response component may be determined by again iteratively solving the system of equations for the columns of each matrix.

Abstract: Various implementations of the invention provide methods and apparatuses for generating a test sequence for a driver and channel combination, wherein the driver is non-linear. In various implementations of the invention, a test sequence is generated that produces the worst or near worst error rate of the channel. With various implementations of the invention, voltage waves at the driver and impulse response waves of the channel are generated. In various implementations of the invention, the driver voltage waves and impulse response waves are simulated responses of the driver and channel to a digital signal input. With further implementations of the invention, receiver voltage waves are generated by combining the impulse response wave and the driver voltage waves. Subsequently, a test sequence is selected based upon the combined receiver voltage wave.