Abstract: A modular rack-mounting system has a rigid, lightweight frame forming a central compartment within which a sleeve is configured to fit, the sleeve having a ventilation configuration to conform with the cooling requirements of an instrument to be inserted within the sleeve. A flat, steel spring is mounted on the side of the frame so that a button extends through a hole in the side to engage a corresponding hole in the side of the sleeve when the sleeve is inserted into the compartment. For a half-rack mount a central rib is included in the frame to divide the central compartment into two compartments, the sleeve being configured to fit into either of the two compartments. Buttons on steel springs are mounted on opposing sides of the central rib to engage the corresponding holes in the sleeves when the sleeve is inserted into either compartment. To release and exchange the sleeves, the buttons at the interior of the sleeves are pushed to allow the sleeves to be removed.

Abstract: A method of indicating and manipulating a zoom region of a waveform being displayed includes a zoom region indicator. The zoom region indicator has an associated marker that spans the zoom region but is never less than a minimum span to allow ease of identifying or locating the zoom region on the displayed waveform. Manipulating the associated marker with a pointer device causes the zoom region to move accordingly along the displayed waveform. The portion of the displayed waveform that is within the zoom region is displayed as a zoomed waveform on the display.

Abstract: A status ribbon to display a signal characteristic for multiple channels/codes within a region of interest has a plurality of stripes. A value for each stripe is represented by a trait of the stripe, such as color or brightness. The trait may represent a range of a signal parameter or may represent a pass/caution/fail value for the signal parameter, or may represent code activity. A window may be used to select a subset of channels/codes for additional detail, the additional detail being displayed textually adjacent the status ribbon. Also a subsidiary status ribbon may be displayed for channels/codes where each stripe of the primary status ribbon represents more than one channel/code, each stripe in the subsidiary status ribbon representing a single channel/code.

Abstract: A word recognizer for providing a channel-to-channel compare for an input digital signal divides channels of the input digital signal into equal-width input signal channel paths. One input signal channel path serves as a reference value for comparison with the other input signal channel path to produce the channel-to-channel compare.

Abstract: A display of code domain power (CDP) for a code domain multiple access (CDMA) signal having multiple spreading factors is in the form of a three-dimensional graphic having as axes code domain power, code index and spreading factor to provide a visual indication of both power and spreading factor for active codes. Sub-codes of base codes may be identified by any suitable means, such as highlighting. Sub-codes may be suppressed and the power level of the base codes adjusted accordingly to represent the total power of the active codes.

Abstract: A luminance qualified vector display device provides a vector display that is gated by a specified luminance range. In one implementation three luminance gates may be used, one for luminance levels above a specified high luminance threshold, a second for luminance levels below a specified low luminance threshold, and a third for luminance levels between the specified high and low luminance thresholds. Also the luminance thresholds for the medium luminance range may be separately adjusted to overlap the high and low luminance ranges respectively. Each luminance qualified vector display may be displayed separately, may be overlaid for display using a different color for each luminance range, or may be displayed in different quadrants of a display device or window together with the normal, non-luminance qualified, vector display.

Abstract: A method of measuring relative channel delay between components of a video signal includes removing a local mean from each of the pair of input component signals and cross-correlating the resulting pair of input component signals. A mean is removed from the cross-correlation and a centroid for the cross-correlation is found within a region bound by nearest zero-crossing to a peak in the cross-correlation. The centroid is then converted to a delay time as a function of sample rate after removing a sample offset. Also a normalized peak value of the cross-correlation provides a figure of merit for the probable accuracy of the delay measurement.

Abstract: A method of creation/editing masks/waveforms for an instrument invokes a mask editor from an application running on the instrument. A context or signal waveform displayed in the application is transferred as a reference to a mask editor graphic display together with an unrelated current mask, which may be a previously existing mask or a default mask. The current mask is edited with respect to the reference to define a new mask, such as by changing the positions of points, adding points or deleting points that define the current mask. Then the mask editor is exited and the application recalled, with the new mask being applied to the context in the application.

Abstract: An FFT accelerated display mode for a spectrum analyzer processes time domain samples in increments as they are received until a complete measurement frame of samples is processed to provide a desired frequency resolution. After a first set of time domain samples is received, a spectrum analysis display is provided having a coarse frequency resolution. Then the spectrum analysis display is updated at intervals as more and more time domain samples are received until the complete measurement frame is processed, providing the desired frequency resolution for the spectrum analysis display.

Abstract: A high frequency sweep generator uses a DDS-PLL method for frequency sweep over wide frequency spans. A digital sweep generator produces a linear ramp signal using DDS techniques that is applied to a coarse tuning port of a high frequency tunable oscillator, such as a YIG tunable oscillator (YTO). A PLL has as inputs an accurate linear swept frequency sinusoid from a DDS and a linear swept frequency output signal from the YTO to produce an error correction signal that is applied to a fine tuning port of the high frequency tunable oscillator. The error correction signal compensates for any non-linearities introduced into the linear swept frequency output signal by the high frequency tunable oscillator.

Abstract: A video field rate persistence is provided for a video waveform display where multiple video components are displayed simultaneously, one component being updated per field interval. A persistence count is assigned to each pixel in a circular field buffer which is divided equally into a number of sub-buffers representing a portion of a display raster, one for each component. The persistence count is updated for each update of the circular field buffer with the pixel values being maintained until the persistence count equals a maximum value, at which point the pixel values for that component are updated with new pixel values. In this manner the display pixels for each component are updated every X video fields and are maintained at their prior values between updates to provide a flicker free display without temporal separation.

Abstract: A multi-instrument triggering system includes in each instrument trigger system a system ready line for coupling an internal ready signal to an external port. A multi-instrument trigger bus cable connects the external ports, trigger event outputs and trigger event inputs of multiple instruments together in such a way as to enable the trigger generators in the instruments when all instruments are ready to receive a trigger event. When enabled, a coordinated trigger is generated in response to an internal trigger event from at one of the instruments. The coordinated trigger is coupled via the multi-instrument trigger bus cable as the trigger event to trigger all instruments in synchronism.

Abstract: The present invention relates to a protocol test device including a network processor where the network processor has the following features: protocol levels of a protocol stack can be programmed in it for at least one protocol per software; it is capable of simultaneously processing input signals of different transmission formats, in particular of different clock rates; a plurality of channel ports for network subscribers in parallel architecture; and one standardized interface for a control unit; with the network processor being designed for in-stream operation, i.e. signals arriving at the ports for network subscribers can be redirected to at least one other port for network subscribers, if necessary after a pre-processing step. A host processor which has been programmed for performing protocol emulations and/or simulations is coupled to the network processor, with the signals of the network subscribers forwarded to the channel ports terminating in the protocol test device.

Abstract: A method of software clamping a video signal for waveform display on a general purpose oscilloscope where the video signal is a.c. coupled to an input of the oscilloscope includes acquiring samples of the video signal in response to a trigger signal derived from the video signal, which samples are then stored. Then samples relative to the trigger signal that are at a nominally known voltage are retrieved, averaged and compared to a reference value. The reference value may be a value determined from a first acquisition of the video signal or a value corresponding to the nominally known voltage. The difference between the averaged samples and the reference value is then used to adjust the sample values when retrieved for display by the oscilloscope.

Abstract: A time history display of orthogonal code power levels by spreading factor is generated by displaying each data record of code domain power as a line, with each point in the line representing a different code index and the color or brightness of each data point representing the associated base code power level. With the data records displayed as contiguous lines, as each new data record is acquired it is added as a new line of the display while the line representing the oldest data record is deleted from the display. For communications standards where the code spreading factor varies, both bit-reversed and Walsh code graphs are displayed to show the grouping of the sub-codes that make up a base code. In this way the time history display indicates timing and trend information to a user.

Abstract: A method for the dynamic control of the channel use of a transmission channel as well as a load generator for sending a test sequence generates the test sequence with several test patterns in accordance with a communication protocol to be used for transmission, preferably using a text editor and fixed definitions. A target channel use is defined. Then a predeterminable number of test patterns from the test sequence are sent and actual channel use is determined. Based on actual channel use a number of filler characters or a waiting time are determined for fixing the target channel use. Then the number of characters are sent or the waiting time is implemented until the next set of test patterns are sent. When all the test patterns of the test sequence have been sent, the transmission is terminated.

Abstract: An activity display for multiple data channels over a period of time for a communication link provides a quasi-three-dimensional presentation having time periods and data channels as orthogonal axes and shading within each time period/data channel rectangle representing ones density for the channel during that time period. One or more frames of the communication link corresponding to one time period are captured, and then each frame is processed in sequence one data channel at a time to build up a line of the display for the time period. Over multiple time periods the display is built up line by line, with the oldest line being dropped as a new line is added when the maximum number of lines for the display is achieved. In this way an operator has a high level all-in-one glance at the operation of the communication link.

Abstract: A picture quality diagnostics apparatus and method generates a human vision model response based on a human vision model for a test input video signal. Also objective measure maps for different impairment types are generated from the test input video signal. The objective measure maps are applied as masks to the human vision model response to produce objectively filtered subjective maps. The objectively filtered subjective maps are analyzed to give the respective proportions of the different objective impairment types contributing to perceptual impairment or difference for the test input video signal.

Abstract: A method for determine blurring in a test video sequence due to video processing includes detecting blocks within each frame of the test video sequence that have valid image edges. An edge point within each valid image edge block is selected and a series of points defining an edge profile in the block along a line normal to the valid image edge at each edge point is defined from an enhanced edge map in which video processing blockiness artifacts have been removed. From the edge profile a blurring value is estimated for each frame or group of frames within the test video sequence. Additionally a reference blurring value may be derived from a reference video sequence corresponding to the test video sequence, which reference blurring value may be generated at a source of the reference video sequence and transmitted with the test video sequence to a receiver or may be generated at the receiver.

Abstract: A wide dynamic range vector data raster display of a waveform image is obtained by using a small matrix of pixels from a source frame buffer containing waveform image data to calculate a value for each pixel on a target display. Any of several algorithms may be used for this transform function, such as the unsharp masking (USM) algorithm used in digital photography. This results in increasing the dynamic range of the displayed waveform image over simple pixel-by-pixel intensity mapping.