Abstract: A wander gamut display for perturbation analysis is created by determining from a periodic input data signal and a reference clock a frequency offset and frequency drift rate for the input signal. The frequency offset and frequency drift rate are input to respective orthogonal axes of a Cartesian display together with a wander limit bounding box that defines the wander gamut. Values that fall outside the bounding box on the display indicate wander that may result in data errors.

Abstract: A method of drawing a waveform image in a no dead time acquisition system, where consecutive drawing frames overlap, uses a master/slave relationship between two fast rasterizers. The master rasterizer draws a first display frame in response to a first trigger event in a trigger signal derived from an input signal. The slave rasterizer draws a second display frame in response to a subsequent trigger event in the trigger signal. The portion of the second display frame that duplicates data contained in the first display frame is either (a) suppressed when the first and second display frames are combined to form the waveform image or (b) displayed in a different shade/color.

Abstract: Aspects of the present invention are related, in general, to Type-III phase-locked loops. In particular, aspects of the present invention relate to analog Type-III phase-locked loop anangements comprising at least two signal paths, wherein each signal path may correspond to a bandwidth partition and may be selected by a selector according to a bandwidth parameter value. According to one aspect of the present invention, a first signal path may correspond to a fast loop (wide closed-loop bandwidth), and a second signal path may correspond to a slow loop (narrow closed-loop bandwidth).

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: A portion of a signal under test corresponding to a portion of interest in an eye pattern is easily identified. An eye pattern display area displays an eye pattern that is derived from sample data of a signal under test in a bitmap form and shows frequency information with colors or brightness. A user selects an arbitrary point on the eye pattern display area with a cross-hair shaped mouse cursor, by manipulating a mouse. Thereafter, a waveform passing through the selected point is discriminably displayed, for example, with highlighted display on the eye pattern. Further, the corresponding portion of a waveform in the waveform display area is distinguishably displayed, such as with a highlighted display.

Abstract: A method and apparatus for improved video bandwidth resolution in DFT-based spectrum analysis is disclosed. A first embodiment comprises an emulation of a continuous range of video bandwidths in DFT-based spectrum analysis using overlapping resolution bandwidth frames. A second embodiment utilizes frame weighting to reduce the standard deviation in the spectrum of noise signal to emulate a corresponding standard deviation of a specified video bandwidth.

Abstract: A sequential equivalent-time sampling oscilloscope simultaneously acquires samples of a signal-under-test and a reference clock that is asynchronous with the signal-under-test. The oscilloscope converts the samples of the reference clock into timestamps and uses the timestamps to compensate for the jitter of the oscilloscope and to indicate the absolute jitter of the signal-under-test.

Abstract: A method of attaching measurement data to an area map on the display of a test instrument includes importing a map for display covering a desired spatial region. Appropriate points of interest are overlaid on the map. A user selects measurement data to be attached to the map and, upon selection such as by “tapping” a touch sensitive screen, a measurement icon is positioned on the map where the selected measurement data was acquired. A thumbnail of the selected measurement data is overlaid on the measurement icon to show both the type of measurement and actual measurement results. Also indicia of quality/strength for the measured signal may be tagged to the measurement icon, such as by changing the color of the border of the measurement icon accordingly. A direction arrow may also be associated with the measurement icon to indicate an orientation of the test instrument when the measurement data was selected.

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: The present invention relates to a method for allocating at least one parameter to at least one transmission channel at an interface disposed between a first node and a second node of a transmission system, wherein the interface is connected to at least one link disposed between the first node and the second node, comprising: a) evaluating the control plane data for determining that a user plane connection including at least one transmission channel for user plane data is to be activated, and determining the associated at least one parameter; b) determining, which at least one transmission channel for user plane data changes its state from inactive to active within a presettable period of time; and c) allocating the at least one parameter to the at least one transmission channel for user plane data.

Abstract: Pre-trigger and post-trigger acquisition for a no dead time acquisition system, where the data being displayed does not include a related trigger event, has a variable record length buffer having a maximum record length equal to a maximum desired pre-trigger interval, and has a trigger FIFO and timer for delaying the related trigger event. The record length of the buffer is determined by the desired pre-trigger interval, and fast rasterizers access the oldest data that encompasses the desired pre-trigger data. A first trigger event in the trigger signal may be delayed by a desired post-trigger interval before the fast rasterizers begin drawing the waveform data that encompasses the desired post-trigger data.

Abstract: A realtime video quality measurement instrument may be configured for both double-ended and single-ended operation. For double-ended operation reference and test video signals are stored in respective buffers and spatial/temporally aligned. Desired quality measurements are performed on the aligned frames of the test and reference video signals according to stored setup instructions. For single-ended operation the reference video signal and a signature for the reference video signal are pre-stored together with the desired quality measurements for the frames of the reference video signal. Then the test video signal is received, signatures determined, and the test and reference video signals aligned using the signatures. The desired quality measurements are then performed on the aligned frames of the test and reference video signals.

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 system and method are provided to generate a histogram of jitter peak values within histogram hardware. The histogram is then transferred to a jitter analyzer, which is implemented in either dedicated hardware or software running on a general purpose processor. The jitter analyzer calculates a cumulative distribution function (CDF) array and a complementary cumulative distribution function (CCDF) array based upon the histogram, and determines the peak jitter values based upon a probability value.

Abstract: A variable passband ARMA filter has as inputs a signal to be filtered, a reverse version of the signal to be filtered and a variable coefficient to produce as an output a filtered signal. The variable coefficient is generated by a variable equivalent sample rate coefficient converter having as inputs an initial coefficient and a variable resampling rate parameter which controls the passband.

Abstract: Determination of speech latency across a communication network element having an input interface and an output interface includes allocating a timestamp to the data packets of a sample of data packets representing a speech signal at the two interfaces, recording the timestamps together with the corresponding data packets, decoding the recorded data packets at both interfaces to generate respective envelopes in the time domain, cross-correlating the envelopes to determine correlating areas of the envelopes, and determining a value for the speech latency between the interfaces from the timestamps associated with correlating areas of the envelopes.

Abstract: A system and method for communication monitoring in a mobile radio network uses a distributed system having one or more processing devices coupled to different links of a serving switching entity of the mobile radio network. The processing devices extract current deciphering parameters from data on the different links, including an additional deciphering parameter set obtained from a subscriber data base entity, from the data flow of the connection, and from each packet data unit as the sequence number of data packets (PDUs) making up the data. The current deciphering parameters are stored in a deciphering parameter providing device so they are available for other processing devices upon request, the deciphering parameter providing device being coupled to the processing device(s) by a communication link such as a LAN or WAN.

Abstract: A method and apparatus for residual spur avoidance is disclosed. One embodiment comprises a method of generating a first local oscillator signal, mixing the first local oscillator signal with a radio frequency signal to generate an intermediate frequency signal, filtering the intermediate frequency signal at a band-pass frequency, mixing the filtered intermediate frequency signal with a second local oscillator signal having a first frequency offset from the band-pass frequency to generate an output intermediate frequency signal, and switching the second local oscillator signal to a second frequency offset to avoid a spur generated from the first frequency offset, wherein the second frequency offset is the opposite sign but same magnitude offset from the band-pass frequency.

Abstract: A phase-locked loop including a phase detector configured to receive inputs from a reference signal path and a feedback signal path and generate a phase detector output based upon such inputs. The phase-locked loop also includes an oscillator operatively coupled with the phase detector and configured to produce an oscillatory output in response to and based upon the phase detector output, and where the oscillatory output is applied to the feedback signal path. The reference signal path includes a mixer configured to mix a reference signal with output from a direct digital synthesizer; and a switching mechanism configured to selectively place one of a plurality of different filters in series between the mixer and the phase detector.

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. A bridge is connected to at least the first and last processors. A system bus connects the bridge to an acquisition module. The acquisition module has a signal bus interface with the system bus being connected to the acquisition module and having its own acquisition hardware. The acquisition hardware is a direct memory access machine that can transfer data to any portion of the memory. There is a signal source connected to the signal bus interface.