Abstract: Apparatuses for a test and measurement instrument provide an instrument capable of handling acquisition, transfer, analysis, and display of large quantities of waveform data and complex waveforms. The apparatus for a test and measurement instrument consists of multiple processors with each processor being connected to its own memory controller. Each memory controller is connected to its own memory. The processors are connected in a circular arrangement by multiple high-speed interconnects. There are multiple bridges with each processor being connected to its own bridge. There are multiple system buses with each bridge been connected to its own system bus. A housing encloses the processors, memory controllers, high-speed interconnects, and bridges.

Abstract: A method of analysis of long record length data using mark duration includes displaying together with a portion of the long record length data each mark that identifies a specified feature of interest together with the mark duration. Associated with the mark may be text identifying the feature of interest, measurement values associated with the duration of the mark, or a combination thereof. Multiple sets of marks may be generated for the long record length data, which sets may be combined to generate new marks with duration. The marks also may be filtered to further refine the marks to be displayed according to user specified criteria. In this way analysis of long record length data representing an acquired signal may be readily automated so a user may move from one interesting event to another without having to pan through the long record length data.

Abstract: A differential measurement probe has a ground clip system for electrically coupling outer shielding conductors of differential probing tips together. In one embodiment, the probing tips independently move vertically relative to each other with the ground clip system secured to each of the outer shielding conductors of the probing tips. In a further embodiment, the probing tips move both vertically and horizontally and the ground clip system has a spring wire member that is secured to the probe. The spring wire member is formed with various sections having various angles to each other that allows one section to slidably engage one of the outer shielding conductors on one of the probing tips and another section to slidably engage the outer shielding conductor of the other probing tip.

Abstract: A data management method for a long record length memory that is used for data acquisition writes data samples into an initial circular buffer within the memory having a size equal to a pre-trigger time. When a first trigger event occurs, the data samples are then written into a linear region after the circular buffer within the memory. The data sample acquisition in the linear region continues until a post-trigger and new pre-trigger time have elapsed after a last trigger event, at which point the acquisition terminates and the new pre-trigger time becomes a new circular buffer for a next trigger event. In this way all trigger events are captured with associated pre-trigger and post-trigger data.

Abstract: A system and method for subscriber tracking and creating subscriber records in a GPRS network is disclosed. First subscriber records are created using information from first data packets captured from a first GPRS network interface. The first subscriber record is compared with information in second data packets captured from a second GPRS network interface. If the second data packets are associated with the first subscriber record, then information from the second data packets is added to the first subscriber record. If the second data packets are not associated with the first subscriber record, then a second subscriber record is created using information in the second data packets.

Abstract: Time variation of phase noise characteristics is displayed for measurement. A peak power of a signal under test is detected to define the frequency as a reference frequency. An offset frequency from the reference frequency is repetitively changed and each time the phase noise power is integrated for a predetermined frequency width to evaluate an integration value. The integration values are divided by the predetermined frequency width. The divided values are further divided by the peak power to evaluate noise power ratios relative to the peak power. Then, relationship between the offset frequencies, noise characteristic values and time is displayed in a graph that shows the time variation of the phase noise characteristics.

Abstract: A wide bandwidth attenuator input circuit for a measurement probe has a Z0 attenuator circuit coupled in series with a compensated RC attenuator circuit. The series attenuator elements of the Z0 and the compensated RC attenuator circuits are coupled via a controlled impedance transmission line to the shunt attenuator elements of the Z0 and the compensated RC attenuator circuits. The shunt element of the Z0 attenuator element terminates the transmission line in its characteristic impedance. The junction of the series and shunt attenuator elements are coupled to the input of a buffer amplifier. At low and intermediate frequencies, the compensated RC attenuator circuit attenuates an input signal while at high frequencies, the compensated RC attenuator circuit acts as a short and the Z0 attenuator circuits attenuates the input signal.

Abstract: Automatic generation of a frequency domain mask is achieved by drawing a reduced waveform representing frequency domain data for an input signal as a pixel map. The reduced waveform is blurred by applying a user selected frequency offset, and from the blurred waveform data points are selected to generate upper and lower limits. The selected upper limit data points form an upper limit mask and the lower limit data points form a lower limit mask. When the upper and lower limit data masks are combined and translated back to frequency/amplitude units from the pixel map, they form an envelope mask.

Abstract: A probing adapter has a support member receiving a probing tip assembly having probing arms. The probing tip assembly is mounted to the support member via a rotational joint having elastomeric member disposed in the probing arms with each of the probing arms having a pivot point disposed away from the rotational joint. Each of the probing arms supports a removable probing tip substrate having a probing tip at one end electrically coupled via an electrical signal conductor to an electrical connector at the other end. Substrate retention clips secure the removable probing tip substrates to the probing arms. A probing tip positioning member is mounted to the probing arms for varying the distance between the probing tips on the removable probing tip substrates.

Abstract: An apparatus for displaying a digitized waveform includes an overview display configured to display a digitized waveform scrolling across the overview display, a zoom display configured to display a portion of the digitized waveform, and a control unit configured to cause the portion of the digitized waveform displayed in the zoom display to track the displayed portion of the digitized waveform in response to a track signal.

Abstract: A system and method for measuring user-perceived delay in an IP network, comprising detecting request and corresponding response messages at a monitoring point in the network, calculating an uplink delay based upon the time elapsed between the request and corresponding response messages, detecting response and corresponding transport acknowledgement messages at the monitoring point, wherein the response message is sent in response to the request message, calculating a downlink network delay based upon the time elapsed between the response and corresponding transport acknowledgement messages; and calculating a user-perceived delay by adding uplink delay and downlink network delay, wherein the user-perceived delay represents a time required for an IP message to travel from a user device to a network destination plus the time required for the service (server) to respond and return the response to the user device.

Abstract: An apparatus for creating a protocol stack has at least one protocol layer with at least one standardized interface and an instance for the administration of the protocol stack. The protocol stack is created by making available the protocol layer(s), randomly compiling the protocol stack from the protocol layer(s), and making available an instance for the administration of the protocol stack using a graphical user interface.

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: A system and method for subscriber tracking and creating subscriber records in a GPRS or UMTS network is disclosed. A local mapping record is created on a probe monitoring a Gi interface upon the detection of Access Start messages. Additional information is sent from a probe monitoring a Gn/Gp interface, and this information is added to the local mapping record. The processing of captured messages and the creation of local mapping record is prioritized to ensure that records for different subscribers who used the same IP address are not improperly combined. Finally, Gi traffic is tagged with unique subscriber information, such as the International Mobile Subscriber Identity (IMSI), not previously present on the Gi network.

Abstract: Timebase variation compensation in a measurement instrument is achieved by simultaneously acquiring both a signal under test and a reference signal. The reference signal is derived from a source that has very stable timing with respect to the timebase. Timing variations are measured from the acquired signals. Timing variations detected in the reference signal are deemed to reflect variations in the timebase of the test and measurement instrument. The timing variations in the reference signal are used to detect, and compensate for, timebase variation in the signal under test to produce a corrected signal under test that reflects the actual timing variations present in the signal under test.

Abstract: An analysis display GJ1 has a coordinate plane of which coordinate axes are elapsed time and PCR (Program Clock Reference) time calculated using PCR extracted from header information of a transport stream packet. A box indicator representing an access unit is provided on the coordinate plane and sides of the box indicator indicate an arrival time of the access unit AU and time of time stamps PTS/DTS. It analyzes the PCR in a transport stream layer and the time stamps PTS/DTS in a PES layer in a manner of over layers, and displays an analysis result that allows easily understanding a relationship between system timing and them. Therefore, it makes it easier to check a problem on the PCR and the time stamps PTS/DTS.

Abstract: Apparatus and methods are provided to allow multiple, possibly overlapping, regions of interest within a frequency spectrum to be defined, and managed. Each of these regions of interest may be selected for further testing or identification. Unselected regions are allowed to collapse into narrow bars so as not to interfere with the selected region. Multiple rows are provided to allow for the definition and selection of overlapping regions of interest. Furthermore, in some embodiments aid is provided for identifying the signal type by providing a list of signal type candidates based upon such parameters as region of interest bandwidth, region of interest center frequency and geographic location.

Abstract: A test and measurement instrument and a method of calibrating the test and measurement instrument including a reference signal generator; multiple input channels; and multiple input circuits. Each input channel is coupled to a corresponding input circuit; and one of the input circuits is coupled to the reference signal generator.

Abstract: An eye violation and excess jitter trigger for a digital signal uses a mask within a unit interval of the digital signal, such as a rectangular mask having corners defined by a high threshold, a low threshold, an early clock and a late clock, the early and late clocks being derived from a reference clock. The reference clock may be a recovered clock derived from the digital signal or from high and low threshold comparator outputs, or may be an external clock. For the excess jitter trigger, which is a special case of the eye violation trigger, the high and low thresholds are essentially equal. A status of the digital signal with respect to the mask is determined using the high and low thresholds and the early and late clocks, and a violation signal is output when the status indicates that a portion of the digital signal crossed into the mask. The violation signal may then be used to trigger data acquisition or for other purposes.

Abstract: An accessory device voltage management system includes an accessory device selectively coupled to a host. The host provides a bulk power supply and a low power supply voltage to the accessory device. The host receives accessory device parameters from the device and determines if the accessory device is a valid and supported device and, if so, sends commands to the accessory device to couple the bulk power supply voltage to a power supply circuit in the accessory device. The power supply circuit in the accessory device generates at least a first regulated voltage output.