Abstract: A pulse response for a receiver, as an array PR, is found from the receiver's symbol stream. For a continuous stream of arbitrary data, a value of the array PR[k] can be determined from the signal levels of the symbols received. The stream of received data is input to a FIFO. Between the first and last locations of the FIFO is the symbol referred to herein as Dn. Symbols located in the FIFO before Dn are referred to as Dn?x. Symbols located in the FIFO after Dn are referred to as Dn+x. Dn differs from the other FIFO symbols in that its signal level can be measured with an adjustable error slicer. The ISI effect of any Dn?k upon Dn can be measured, and thus any PR[k] measured, by measuring the average signal level of Dn when only certain types of data streams occur in the FIFO.

Abstract: The DC offset of a differential signal can be changed by differentially shifting the DC offset of each of its signals. Techniques are presented for changing, in a controlled way, the DC offset of a differential signal as received by a receiver of a data transmission system. Several classes of example embodiments, utilizing digitally controllable voltage or current sources, are presented. The classes differ based upon such factors as coupling capacitor arrangement and use of termination resistors. Specific embodiments, within each class, differ based upon such factors as whether voltage or current sources are used and the characteristics of such sources. Once the DC offset of a differential signal has been changed, the effect of such change on a performance metric can be measured. Example applications include the ability to determine a differential signal level that results in BER having a particular level and determination of differential signal margin.

Abstract: A pulse response for a receiver, as an array PR, is found from the receiver's symbol stream. For a continuous stream of arbitrary data, a value of the array PR[k] can be determined from the signal levels of the symbols received. The stream of received data is input to a FIFO. Between the first and last locations of the FIFO is the symbol referred to herein as Dn. Symbols located in the FIFO before Dn are referred to as Dn?x. Symbols located in the FIFO after Dn are referred to as Dn+x. Dn differs from the other FIFO symbols in that its signal level can be measured with an adjustable error slicer. The ISI effect of any Dn?k upon Dn can be measured, and thus any PR[k] measured, by measuring the average signal level of Dn when only certain types of data streams occur in the FIFO.

Abstract: A pulse response for a receiver, as an array PR, is found from the receiver's symbol stream. For a continuous stream of arbitrary data, a value of the array PR[k] can be determined from the signal levels of the symbols received. The stream of received data is input to a FIFO. Between the first and last locations of the FIFO is the symbol referred to herein as Dn. Symbols located in the FIFO before Dn are referred to as Dn?x. Symbols located in the FIFO after Dn are referred to as Dn+x. Dn differs from the other FIFO symbols in that its signal level can be measured with an adjustable error slicer. The ISI effect of any Dn?k upon Dn can be measured, and thus any PR[k] measured, by measuring the average signal level of Dn when only certain types of data streams occur in the FIFO.

Abstract: An eye opening measurement technique, that does not interrupt a receiver's normal operation, is used as a metric for optimizing any selected parameters of the receiver's operation. If eye opening size decreases, as a result of a change to a receiver parameter, the polarity for stepwise changes is reversed such that the next change is in the opposite direction. Other types of search procedures can be used. Eye opening size is the difference between the eye's upper and lower edges. Measurement of eye opening size is accomplished using a data and auxiliary slicer that find each “edge” of an eye opening based upon the slicers' level of agreement. Depending upon the level of agreement, and whether symbols of the upper or lower region of the eye are counted, the threshold of the auxiliary slicer can be adjusted in the direction necessary to converge on the eye edge sought.

Abstract: An eye opening measurement technique, that does not interrupt a receiver's normal operation, is used as a metric for optimizing any selected parameters of the receiver's operation. If eye opening size decreases, as a result of a change to a receiver parameter, the polarity for stepwise changes is reversed such that the next change is in the opposite direction. Other types of search procedures can be used. Eye opening size is the difference between the eye's upper and lower edges. Measurement of eye opening size is accomplished using a data and auxiliary slicer that find each “edge” of an eye opening based upon the slicers' level of agreement. Depending upon the level of agreement, and whether symbols of the upper or lower region of the eye are counted, the threshold of the auxiliary slicer can be adjusted in the direction necessary to converge on the eye edge sought.

Abstract: Probability distribution functions (PDFs), of a periodic input data signal, can be used to provide eye-diagram information. An advantage of PDFs, over conventional approaches to eye-diagram collection, is that analog-to-digital conversion can be accomplished by the slicer of a receiver, provided the slicer can programmably change its threshold. A cumulative distribution function (CDF), at a particular phase of a desired eye-diagram, can be collected by having a receiver's slicer scan its threshold level. For each threshold level, a fixed number of symbols can be analyzed as follows to produce a CDF value: count the number of times a particular symbol value occurs. The derivative of a CDF can produce its PDF, where each PDF can represent a “slice” of a desired eye-diagram. For a non-periodic input signal, an eye diagram can still be formed so long as the percentage occurrence, of each symbol value, remains at least approximately the same.

Abstract: An eye opening measurement technique, that does not interrupt a receiver's normal operation, is used as a metric for optimizing any selected parameters of the receiver's operation. If eye opening size decreases, as a result of a change to a receiver parameter, the polarity for stepwise changes is reversed such that the next change is in the opposite direction. Other types of search procedures can be used. Eye opening size is the difference between the eye's upper and lower edges. Measurement of eye opening size is accomplished using a data and auxiliary slicer that find each “edge” of an eye opening based upon the slicers' level of agreement. Depending upon the level of agreement, and whether symbols of the upper or lower region of the eye are counted, the threshold of the auxiliary slicer can be adjusted in the direction necessary to converge on the eye edge sought.

Abstract: The DC offset of a differential signal can be changed by differentially shifting the DC offset of each of its signals. Techniques are presented for changing, in a controlled way, the DC offset of a differential signal as received by a receiver of a data transmission system. Several classes of example embodiments, utilizing digitally controllable voltage or current sources, are presented. The classes differ based upon such factors as coupling capacitor arrangement and use of termination resistors. Specific embodiments, within each class, differ based upon such factors as whether voltage or current sources are used and the characteristics of such sources. Once the DC offset of a differential signal has been changed, the effect of such change on a performance metric can be measured. Example applications include the ability to determine a differential signal level that results in BER having a particular level and determination of differential signal margin.

Abstract: The DC offset of a differential signal can be changed by differentially shifting the DC offset of each of its signals. Techniques are presented for changing, in a controlled way, the DC offset of a differential signal as received by a receiver of a data transmission system. Several classes of example embodiments, utilizing digitally controllable voltage or current sources, are presented. The classes differ based upon such factors as coupling capacitor arrangement and use of termination resistors. Specific embodiments, within each class, differ based upon such factors as whether voltage or current sources are used and the characteristics of such sources. Once the DC offset of a differential signal has been changed, the effect of such change on a performance metric can be measured. Example applications include the ability to determine a differential signal level that results in BER having a particular level and determination of differential signal margin.

Abstract: A functional block under test (FBUT), comprising mixed-signal or analog circuits, can be tested by a digital test machine (DTM). A DTM sources test vectors to, and expects to receive certain vectors back from, a DUT. The DUT is a single, physically contiguous, IC upon which is integrated the FBUT, a mixed-signal generate and capture unit (MSGC) and a control system. The test vectors can include computer programs for instructing the control system on how to perform mixed-signal or analog-domain tests of the FBUT using resources of the MSGC (such as DACs and ADCs). The test vectors can also include data that effects the operation of a parameterized test procedure, where the test procedure is part of the control system. The control system, in accordance with the test procedure, uses the MSGC to perform mixed-signal or analog-domain tests of the FBUT. The FBUT can include an analog test bus.

Abstract: In one aspect, the present invention is directed to a technique of, and circuitry and system for enhancing the performance of data communication systems using receiver based decision feedback equalization circuitry. In one embodiment, the equalization circuitry and technique employs a plurality of data slicers (for example, two) to receive an analog input and output a binary value based on the reference or slicer level. The output of the data slicers is provided to logic circuitry to determine whether the analog input was a binary high or binary low. In those instances where the data slicers “agree” and both indicate either a high or a low, the logic circuitry outputs the corresponding binary value. In those instances where the data slicer do not “agree”—that is, where one data slicer indicates the input to be a binary or logic high value and the other data slicer indicates the input to be a binary or logic low value, in one embodiment, the logic circuitry outputs the complement of the previous binary value.

Abstract: In one aspect, the present invention is a technique of, and a system and sensor for measuring, inspecting, characterizing and/or evaluating the performance of high-speed data communication systems, and components used therein. In one embodiment, the present invention measures, inspects, characterizes and/or evaluates the performance, for example the ER, of such systems and/or components in situ—that is, in the environment and/or in the configuration in which the system and/or components are used during normal or typical operation (for example, when the system and/or component is transmitting and receiving user data). In this way, a more accurate representation of the performance of the system (and components thereof) may be measured, detected, determined and/or obtained.

Abstract: In one aspect, the present invention is a technique of, and a system and sensor for measuring, inspecting, characterizing and/or evaluating the performance of high-speed data communication systems, and components used therein. In one embodiment, the present invention measures, inspects, characterizes and/or evaluates the performance, for example the ER, of such systems and/or components in situ—that is, in the environment and/or in the configuration in which the system and/or components are used during normal or typical operation (for example, when the system and/or component is transmitting and receiving user data). In this way, a more accurate representation of the performance of the system (and components thereof) may be measured, detected, determined and/or obtained.

Abstract: In one aspect, the present invention is a technique of, and a system and sensor for measuring, inspecting, characterizing and/or evaluating the performance of high-speed data communication systems, and components used therein. In one embodiment, the present invention measures, inspects, characterizes and/or evaluates the performance, for example the ER, of such systems and/or components in situ—that is, in the environment and/or in the configuration in which the system and/or components are used during normal or typical operation (for example, when the system and/or component is transmitting and receiving user data). In this way, a more accurate representation of the performance of the system (and components thereof) may be measured, detected, determined and/or obtained.