Abstract: A signal generator produces a victim signal having crosstalk emulation by filtering and combining a victim signal waveform record file and an aggressor signal waveform record file generated using parameters selected by a user. A signal channel or a cascaded signal channel is characterized using one or more S-parameter arrays. The S-parameter array or arrays represent a mixed-mode multiple-port device under test. Coefficients of a NEXT filter, a FEXT filter and a forward transmission filter are derived from selected S-parameters of the S-parameter array. The aggressor signal is filtered individually by the NEXT and FEXT filters. The victim signal is summed with the filtered aggressor signal from the NEXT filter with the resulting summed signal being filtered by the forward transmission filter. The filtered signal from the forward transmission filter is summed with the filtered aggressor signal from the FEXT filter to generate a victim signal having crosstalk emulation.

Abstract: A messaging system and method for creating a messaging hierarchy in a computer network are described. The network is made up of multiple network entities, which include both publishing entities and subscribing entities, where the publishing entities have data of which the subscribing entities may have need. The messaging system and method for creating a messaging hierarchy also include a data hierarchy applied to the data exchanged between the publishing entities and subscribing entities. The data hierarchy determines the virtual connections formed between the network entities in response to publication and subscription requests exchanged between the entities, such that the virtual connections established between network entities form a hierarchy corresponding to the data hierarchy.

Abstract: An apparatus and method corrects for zero ampere level current fluctuations in a current signal. First and second acquisition circuitry generate respective current and voltage data samples of the current signal. Current fluctuation data samples representative of zero ampere level deviations of the current signal are extracted corresponding to Off-periods of the current signal. The current fluctuation data samples of the Off-periods are interpolated to generate current fluctuation data samples representative of zero ampere level deviations of the On-periods of the current signal. The Off-period and On-period current fluctuation data samples are subtracted from the current data samples of the current signal to generate corrected zero ampere level current data samples.

Abstract: A data converter system provides an output signal having reduced spurious tones by confining an input signal to a specified frequency band and over-sampling so that the converted input signal “straddles” or “avoids” spurious tones. The spurious tones may then be filtered away, providing an output signal having a much cleaner spurious free dynamic range than a conventional data converter. For example, in one embodiment, an interleaved data converter system converts an input signal that is confined to the second Nyquist zone of one of the interleaved data converters into an interleaved signal, and then filters the interleaved signal with a filter having a pass-band that transmits the converted input frequencies and a stop-band that attenuates the spurious tones. The resulting output signal has a bandwidth that is the same as could be achieved using a single data converter, but is not impaired by interleave images or certain distortion products.

Abstract: An Arbitrary Waveform Generator (AWG) synthesizes and generates an SSC modulated signal by generating a modulating waveform with a frequency of an SSC modulation frequency, calculating the number of samples per data bit (SPUI) as a ratio of an upsampling frequency to a data rate of a data stream, calculating an amplification factor as the ratio of SSC deviation frequency to data rate of the data stream, generating the array of SSC Edges containing the edge variation with respect to single sample per bit, multiplying the amplification factor to the modulating waveform, generating an array of SSC Edges Upsampled, containing edge variations with respect to an Upsample factor per bit, and multiplying SSC Edges with SPUI; calculating the resultant bit duration SSC Bit Duration as the sum of SSC Edges Upsampled and SPU, and calculating the successive summation of SSC Bit Duration, to get SSC Bit Position.

Abstract: In a multi-channel oscilloscope a method of calibrating interleaved digitizer channels initially calibrates each digitizer channel to produce a bandwidth enhanced filter for each digitizer channel to match the respective channel frequency and phase characteristics. The oscilloscope is then configured for interleaved operation whereby an input signal is applied to at least two digitizers via a switch through a common preamplifier to produce a reference digitizer channel and an interleaved digitizer channel where the bandwidth enhanced filter for the interleaved digitizer channel is now not correct. Fast Fourier transforms are performed on the data from the reference digitizer channel and the interleaved digitizer channel, from which are derived a match filter for the interleaved digitizer channel so the interleaved digitizer channel and reference digitizer channel are matched in phase and magnitude at all frequencies.

Abstract: An improved hold-off algorithm that assures that all data associated with all trigger events in a data signal are displayed uses a designated interval starting with a first trigger event to determine whether any subsequent trigger events occurred within the designated interval. A first display frame is drawn based upon the first trigger event. A next display frame is drawn based either on a next trigger event that occurs outside the designated interval, or based on the last trigger event that occurred within the designated interval. In the latter case the two display frames provide an overlap to assure that no data related to the trigger events is lost on the display.

Abstract: Parameters of a spread spectrum clock signal in a communication signal are characterized by acquiring voltage samples of the communication signal at a nominal time location of an edge of the communication signal. The voltage samples are converted to time samples and the difference between the maximum and minimum time values is determined at the nominal time location. A spread spectrum clock magnitude number is generated by dividing the difference between the maximum and minimum time values by the nominal time location of the acquired voltage samples of the spread spectrum clock signal. A spread spectrum modulation profile of a spread spectrum clock signal is estimated by over sampling the time samples using an aliased index value to generate over sampled triangular waveforms representing the spread spectrum clock modulation profile. One of the over sampled triangular waveforms is use to generate the spread spectrum clock modulation profile.

Abstract: A signal acquisition probe stores compressed or compressed and filtered time domain data samples representing at least one of an impulse response or step response characterizing the signal acquisition probe. The compressed or compressed and filtered time domain data samples of the impulse response or the step response are provided to a signal measurement instrument for compensating the signal measurement instrument for the impulse or step response of the signal measurement instrument.

Abstract: A test and measurement instrument including a time domain channel configured to process a first input signal for analysis in a time domain; a frequency domain channel configured to process a second input signal for analysis in a frequency domain; and an acquisition system coupled to the time domain channel and the frequency domain channel. The acquisition system is configured to acquire data from the time domain channel and the frequency domain channel. Time domain and frequency domain data can be time aligned.

Abstract: A test and measurement instrument including an input port configured to receive an input signal; a digitizer configured to digitize the input signal; a decimator coupled to the digitizer and configured to decimate the digitized input signal to generate a decimated input signal; a digital downconverter coupled to the digitizer and configured to frequency shift the digitized input signal to generate a frequency shifted input signal; and a memory configured to store the decimated input signal and the frequency shifted input signal.

Abstract: Systems and methods for discovering SCTP associations between devices communicating in a network are described. A method comprises monitoring packets communicated among a plurality of source and destination devices, determining a combination of source EP address, source port number, destination IP address, and destination port number that defines an association between a source device and a destination device, and resolving a combination of source and destination verification tags that further defines the association based upon the combination of EP addresses and port numbers. The method further comprises ascertaining whether a subsequently monitored packet belongs to the association based at least in part upon an element of the combination of verification tags after at least one element of the combination of EP addresses and port numbers has changed during the ongoing communication.

Abstract: System and method for automatically detecting nodes, components and interfaces in a network. A preferred embodiment comprises detecting nodes in a network, wherein the nodes are coupled to a network controller, comprises identifying ports for the network controller, capturing messages received by the network controller at the ports, parsing the messages to identify a node address parameter, wherein the node address parameter uniquely identifies the node to the network controller, and if the node address parameter has not been previously identified, adding a new entry to a node database.

Abstract: This invention relates to a system and method of monitoring, by establishing end to end loopback testing across one or more networks with dissimilar transport technologies. The system allows for connection in loopback mode from a standard interface on a test device to a media adaptor located on an IP-based access network, such as a standard multimedia terminal adapter (“MTA”). End-to-End Quality of service delivered over the transmit and receive path can thus be monitored. Loopback tests are initiated from designated endpoints on the network and made operational by attaching a tag to a telephone number, to allow the gateway to signal connection mode to a call agent. The system and method overcome certain inherent limitations of the MGCP/NCS architecture.

Abstract: A data analysis technique for a long data record in a memory uses a reference, either user-provided or calculated from the data in the long data record, as a representative event. Each event in the long data record is compared with the reference to determine whether there are significant deviations from the reference. Those events having significant deviations are identified as events of particular interest for a user. The reference may be either a waveform shape or a mean time interval between events. A tolerance value may be added to the waveform reference and varied for dynamic limit testing. Events that are outside the waveform reference as modified by the tolerance value are identified as outliers and may be reduced to iconic images for display simultaneously with the long data record and a selected one of the outliers.

Abstract: A system and method for enforcing network policies is disclosed. Data is captured from network interfaces. A cell congestion level is determined from the captured data. Cells having a congestion level above a first threshold are identified. A first alert is transmitted to a network policy management entity when the cell is above the first threshold. Cells having a congestion level above a second threshold are identified. A second alert is transmitted to the network policy management entity when the cell is above the second threshold. The first threshold set at a point below a maximum capacity of the cell, and the second threshold set at a point near or at the maximum capacity of the cell.

Abstract: Embodiments of the present invention provide a test and measurement instrument that processes acquired data before it is displayed by re-sampling it with a pseudo-random sampling phase. This data processing step introduces a randomly-varying phase between the signal under test and the sampling clock of the test and measurement instrument, thereby canceling the effect of any synchronization between the two. In this manner, the test and measurement instrument may acquire data based on a clock signal that is very close to, or even synchronized with, the test and measurement instrument's own sampling clock (or a harmonic of it), and yet still provide a smooth, artifact-free display.

Abstract: Embodiments of the invention are directed to a system for generating video test pattern signals from definitions contained in a text-based definition file. The definition file allows the user to create generic definitions for test signals that can be interpreted to create test signals in a variety of formats, raster sizes, color spaces, sample structures, frame modes, and bit depths. A parametric generator uses one or more engines to then generate the desired test pattern from the definition file.

Abstract: A signal generating device has a display, central processing unit and a waveform generating circuit. The central processing unit generates a user interface on the display for setting parameters for a serial data pattern and a parameter for an intersymbol interference and a bandwidth extension pre-emphasis effect on the serial data pattern. A waveform record file is generated using the serial data pattern parameters and the intersymbol interference effect and bandwidth extension pre-emphasis effect parameter. A waveform generation circuit receives the waveform record file and generates a serial data pattern analog output signal having the intersymbol interference effect or the bandwidth extension pre-emphasis effects defined by the intersymbol interference and bandwidth extension pre-emphasis effect parameter.

Abstract: Embodiments of the present invention provide a test and measurement instrument that displays acquired data on a logarithmic scale without intensity banding. The test and measurement instrument processes the acquired data before it is displayed by appending pseudo-random sub-LSB (least significant bit) values to it. When the processed acquired data is displayed on a logarithmic scale, the pseudo-random sub-LSB values fill in the gaps between discrete power levels, thereby eliminating intensity banding and providing a smooth, visually pleasing display.