Abstract: A method of digitizing an analog signal is provided, comprising the steps of separating the analog signal spanning a frequency range into a plurality of frequency bands, and then translating at least one of the signals to a lower frequency band in accordance with a local oscillator and digitizing the at least one translated signal with digitizing elements having a frequency range less than the analog signal frequency range. A fixed relationship of the phase of the local oscillator and a repetitive signal generated in accordance with a writing to a circular buffer of the digitized representation of the at least one of the plurality of frequency bands is then defined. Signals corresponding to the other of the plurality of frequency bands are digitized and written to corresponding circular buffers. Finally, a digital representation of the analog signal is formed from the digitized signals.

Abstract: A physically rotatable display for a test and measurement apparatus is provided.

Abstract: A system for estimating bit error rates (BER) may include using a normalization factor that scales a BER to substantially normalize a Q-scale for a distribution under analysis. A normalization factor may be selected, for example, to provide a best linear fit for both right and left sides of a cumulative distribution function (CDF). In some examples, the normalized Q-scale algorithm may identify means and probabilistic amplitude(s) of Gaussian jitter contributors in the dominant extreme behavior on both sides of the distribution. For such contributors, means may be obtained from intercepts of both sides of the CDF(Qnorm(BER) with the Q(BER)=0 axis, standard deviations (sigmas) may be obtained from reciprocals of slopes of best linear fits, and amplitudes may be obtained directly from the normalization factors. In an illustrative example, a normalized Q-scale algorithm may be used to accurately predict bit error rates for sampled repeating or non-repeating data patterns.

Abstract: In one implementation, a termination circuit may include a variable resistance circuit that comprises a resistance network in which the resistance of a parallel combination of two complementary transistors of opposite types is substantially independent of the drain-to-source voltages of the transistors when the gate-to-source voltages of the transistors are substantially equal in magnitude and opposite in sign. In various examples, the network may include a resistor in parallel and/or series with the transistors. Some implementations may adjust a resistance of the network in response to a digital-to-analog converter output signal. In another implementation, an integrated circuit may include a termination stage with an integrated resistor in parallel or series with a circuit having a tunable impedance. In an illustrative embodiment, relative channel width of the first and second transistors may be selected to realize substantially complementary characteristics for drain-to-source voltage vs.

Abstract: Apparatus and associated systems and methods may relate to a data traffic modification system that may include a processing module to handle SATA-compliant data transfers in which a source device or a target device issues requests to pause and subsequently to resume the data transfer. In various implementations, a data traffic modification device may selectively modify data traffic upon the occurrence of a predetermined condition. In one illustrative example, if a target device for the data transfer issues a pause request (e.g., to prevent a buffer overflow), the data traffic modification device may generate a pause acknowledge signal to the target device within a response time specified by the protocol. In another illustrative example, if a source device for the data transfer issues a pause request, the data traffic modification device may generate a pause acknowledge signal to the source device within the response time specified by the protocol.

Abstract: A system for estimating bit error rates (BER) may include using a normalization factor that scales a BER to substantially normalize a Q-scale for a distribution under analysis. A normalization factor may be selected, for example, to provide a best linear fit for both right and left sides of a cumulative distribution function (CDF). In some examples, the normalized Q-scale algorithm may identify means and probabilistic amplitude(s) of Gaussian jitter contributors in the dominant extreme behavior on both sides of the distribution. For such contributors, means may be obtained from intercepts of both sides of the CDF(Qnorm(BER) with the Q(BER)=0 axis, standard deviations (sigmas) may be obtained from reciprocals of slopes of best linear fits, and amplitudes may be obtained directly from the normalization factors. In an illustrative example, a normalized Q-scale algorithm may be used to accurately predict bit error rates for sampled repeating or non-repeating data patterns.

Abstract: A method and system for measuring the input (loading) impedance of measurement systems using a test fixture. This is done by first measuring the characteristics of an unloaded test fixture to obtain scattering parameters of the test fixture and using a splitting algorithm to calculate the scattering parameters of each transmission line leg of the test fixture. The test fixture is then measured with a measurement system attached. The test fixture effects defined by the scattering parameters are then removed from the measurement to yield the scattering parameters of the measurement system alone (measurement system effects).

Abstract: A waveform processing system performs operations that may include identifying a location of a specified bit pattern within a coherently sampled repeating pattern input signal. In some examples, multiple periods of a repeating pattern signal are acquired using coherent sampling techniques such as, for example, coherent interleaved sampling (CIS). In such examples, the sampled waveform may be converted to a binary pattern that can be searched to locate a match to a predetermined or user-specified bit pattern. In one illustrative example, the identified location may be used to display the sampled waveform. In another example, the identified location may be used to measure pattern-dependent jitter of the sampled waveform.

Abstract: A method is provided for de-embedding measurements from a given network containing mixtures of devices with known and unknown S-parameters given a description of the network and the known S-parameters of the overall system.

Abstract: A method for improving bandwidth of an oscilloscope involves, in preferred embodiments, the use of frequency up-conversion and down-conversion techniques. In an illustrative embodiment the technique involves separating an input signal into a high frequency content and a low frequency content, down-converting the high frequency content in the analog domain so that it may be processed by the oscilloscope's analog front end, digitizing the low frequency content and the down-converted high frequency content, and forming a digital representation of the received analog signal from the digitized low frequency content and high frequency content.

Abstract: A locking mechanism and method for selectively fixing and allowing movement of a tip portion of a probe relative to a rigid portion of the probe are provided. The mechanism comprises a locking ball joint for selectively locking and allowing relative movement between the tip portion and the rigid portion and a sleeve about the ball joint. The locking ball joint is locked by the placement of the sleeve in a first position, thereby fixing the position of the tip portion relative to the rigid portion, and released by the placement of the sleeve in a second position, thereby allowing movement of the tip portion relative to the rigid portion.

Abstract: A method and apparatus for capturing an analog waveform on a serial bus. The method comprises the steps of designating a predetermined digital data sequence, decoding a serial data signal carried on a serial data bus, and comparing the decoded serial data signal to the predetermined digital data sequence. When it is determined that a portion of the decoded serial data matches the predetermined digital data sequence, the portion of the serial data signal corresponding to the matching portion of the decoded serial data signal is marked.

Abstract: A method and apparatus for generating one or more transfer functions for converting waveforms. The method comprises the steps of determining a system description, representative of a circuit, comprising a plurality of system components, each system component comprising at least one component characteristic, the system description further comprising at least one measurement node and at least one output node, each of the at least one measurement nodes representative of a waveform digitizing location in the circuit. One or more transfer functions are determined for converting a waveform from one or more of the at least one measurement nodes to a waveform at one or more of the at least one output nodes. The generated transfer functions are then stored in a computer readable medium.

Abstract: A signal processing system compensates for the relative phase difference between multiple frequency bands so that the combination of the bands is constructive throughout a substantial portion of the band overlap or crossover region. In one embodiment, a signal combining system may include a comparator for determining a relative phase difference between the two signals within a predefined crossover region, a phase adjusting element for adjusting a phase of one of the two signals; and a combiner for combining the phase-adjusted signal and the other of the two signals.

Abstract: A method and apparatus for testing a data transfer system. The method comprises the steps of storing a first table, the first table noting at least a time of issuance of at least one command and a time of completion of the command and comparing the time of issuance of the command and the time of completion of the command. A timeout condition is registered if the processor determines that a time longer than a predetermined time elapsed between the time of issuance of the command and the time of completion of the command.

Abstract: A method and system are provided for determining a location of a predetermined N bit sequence in a data stream. The method comprises the steps of determining two N bit data words from consecutive bits of the data stream, and providing N, N bit comparators. A first N bits of the two N bit data words is compared with the predetermined N bit data sequence by a first of the N comparators, and a next N bits, starting at a second bit, of the two N bit data words are compared with the predetermined N bit sequence by a second of the N bit comparators. These comparisons are repeated, incrementing the starting bit, until N comparators have been employed and the first through N bits have been employed as the starting bit.

Abstract: A conductive connector includes a flexible-deflectable extension having a probing end and a head connection end. A conductive transmission path extends between the probing end and the head connection end. A pogo-rotational-action pin is electrically connected to the transmission path at the head connection end of the flexible-deflectable extension.

Abstract: A probe for probing an electrical device under test is provided. The probe comprises a camera positioned adjacent a probing tip of the probe. Visual information captured by the camera is displayed on a display device. The camera may be mounted in multiple locations as desired by a user and additionally, multiple cameras may be used with the probe to allow for more viewing angles.

Abstract: A method, apparatus and computer program having instructions for storing information in an oscilloscope is provided. The method comprises the steps of storing a screen display in a predetermined format, storing one or more configuration settings associated with the screen display, and storing in memory channel acquisition data associated with the stored screen display. The screen display may also be annotated, the annotation information being stored as well. The stored screen display, one or more associated configuration settings, and stored channel acquisition data, and annotation data, if applicable, may be loaded into the oscilloscope, thereby placing the oscilloscope in the state it was in when the stored data was originally generated.

Abstract: A method and apparatus for generating one or more transfer functions for converting waveforms. The method comprises the steps of determining a system description, representative of a circuit, comprising a plurality of system components, each system component comprising at least one component characteristic, the system description further comprising at least one measurement node and at least one output node, each of the at least one measurement nodes representative of a waveform digitizing location in the circuit. One or more transfer functions are determined for converting a waveform from one or more of the at least one measurement nodes to a waveform at one or more of the at least one output nodes. The generated transfer functions are then stored in a computer readable medium.