Abstract: A data file containing metadata and/or control data is synchronized with associated audio/video data by subliminally embedding a key in a frame of the audio/video. The key indicates the location of the data file and a time after the embedded frame in which the data file is to be activated to be in synchronism with the audio/video. The data file is accessed via an alternate channel and held in a buffer until the time indicated by the key. The metadata from the data file is played out for display in synchronism with the associated audio/video data, and instructions contained in the control data are executed in synchronism with the associated audio/video data.

Abstract: Apparatus for data bus expansion between two instrument chassis comprises a first interface circuit, a connecting cable, and a second interface circuit. Detection circuitry in each interface circuit detects slot position. Slot position determines direction of address and data flow for each card. One of the first and second interface circuits is connected to a controller slot in a first chassis, and the other of the first and second interface circuits is connected to a non-controller slot in a second chassis. Bus interface circuitry for signal and identification are reconfigured in accordance with slot determination. As a result, the assembly formed by connection of two substantially identical interface cards with a cable, is symmetric and reversible.

Abstract: An electronic system includes a source of test data, which, if the test data source is operating properly, is a pattern of a limited number of data words successively repeated. A memory device is coupled to the test data source and stores the test data. A memory test circuit compares the stored test data to successively repeated pattern data words and generates a signal to indicate whether the stored test data is the same as the successively repeated pattern data words.

Abstract: An adapter for a multi-channel, low input capacitance signal probe head has a housing with a cavity formed therein that receives one of a mating plug or receptacle portion of multi-channel, controlled impedance connector. The housing has probe head retention members formed in the sidewalls and alignment flanges disposed adjacent to the probe head retention members that are received in the signal probe head. The adapter includes a substrate having first and second arrays of contact pads formed on the respective top and bottom surfaces of the substrate. The first array of contact pads mate with electrically conductive elastomer signal contacts of the signal probe head and the second array of contact pads mate with the contact pads of the transmission lines of the plug or receptacle. Screws extend through bores in the signal probe head and engage threaded pins in the retention members.

Abstract: A low capacitance probe contact has electrically conductive contacts having fingers with opposing interior flat surfaces forming a slit there between. The fingers extend in a first direction with a mounting member extending in the opposite direction having a flat surface that is parallel to the flat surfaces of the fingers. The first and second electrically conductive contacts are secured to respective first and second electrically conductive contact pads formed on a substrate with the flat surfaces of the mounting members being positioned on the contact pads. The substrate and the electrically conductive contacts are captured within a housing having first and second members. One member has a base and extending sidewalls forming a recess that receives the substrate and the electrically conductive contacts and the other member has a periphery coextensive with the first member to capture the substrate and the electrically conductive contacts therein.

Abstract: A method of broadband receiver amplitude/phase normalization uses internal normalization sources—a thermally compensated noise source and a pseudo random sequence generator. A calibrated signal is applied to the input of the broadband receiver and processed by a digital signal processor to generate a gain versus frequency table. Then the internal noise source is applied to the input of the broadband receiver and process by a digital signal processor to generate a noise level versus frequency table. Finally the internal pseudo random sequence generator applies a pseudo random sequence waveform to the input of the broadband receiver, the pseudo random sequence waveform being process by the digital signal processor to generate equalization filter coefficients for the IF stages.

Abstract: A method of detecting frozen fields in a video signal that has undergone analog encoding at some point along a transmission path acquires the video signal as a digital video signal. Every field of the digital video signal and its nth subsequent field are selected as a pair, where n is an integer multiple of the number of fields required for one cycle of color phasing in the analog encoding. The pairs of the selected fields are compared and, if the difference is essentially zero, a frozen field error is indicated.

Abstract: A measurement test instrument voltage management system for an accessory device has a accessory device interface that provides a voltage to a memory device in the accessory device. A sensing circuit receives a sensing signal from the accessory device when it is connected to the interface. The sensing circuit generates an interrupt signal that is coupled to a controller. The controller initiates the generation of a clock signal that is coupled to the accessory device through the interface to retrieve accessory device data stored in the device memory. The controller determines if the connected accessory device is a valid device capable of being supported by the measurement test instrument. The controller generates an enable signal for a valid and supported device that is coupled to a voltage switching circuit. The voltage switching circuit generates at least a first output voltage that is coupled to the accessory device via the interface to provide power to the accessory device.

Abstract: An incremental bus structure for a modular measurement instrument includes interface connector structural elements interconnecting segments of a system bus. The system bus contains electrically conductive lines with the system bus having at least one subset of N electrically conductive lines. Each interface connector is part of a measurement module and has at least one set of N electrically conductive input and output contacts corresponding with the N electrically conductive lines. The first input contact of the set of N contacts for each connector is coupled to an electronic element associated with its measurement module and the second and subsequent input contacts are connected to the first and subsequent output contacts.

Abstract: Apparatus for monitoring a signal at an intermediate point on a series impedance source terminated unidirectional transmission line employs a voltage probe, a current probe, and a summing element. The apparatus provides a useful output signal despite the fact that signals at an intermediate point on the transmission line comprise the sum of incident and reflected waveforms. The voltage probe derives a signal from the transmission line that is representative of the sum of the incident and reflected waveforms. The current probe produces a voltage signal representative of the difference between the incident and reflected waveform currents. The summing circuit algebraically adds the output signals of the voltage and current probes, and produces an output signal representative of only one of the transmitted waveform or the reflected waveform.

Abstract: A “Streaming Distributed Oscilloscope” (SDO) architecture comprises at least one channel including a preamplifier module, a Digitizer Module, and an Acquisition Memory Module. An SDO couples all acquired samples of a waveform being monitored to all of its processing boards. Because multiple processor boards can access all of the sample data, an SDO can perform measurements on substantially all samples of a continuous data stream without dead time. An SDO is readily expandable in terms of memory length by simply adding more memory boards, and can be reconfigured by a user by virtue of its object-oriented architecture. An SDO waveform is defined by a trigger source and an acquisition memory. An SDO is capable of acquiring multiple waveforms based upon different triggers from the same data stream in the same channel. An SDO timebase for a given channel is defined by a decimator followed by an acquisition memory. Multiple timebases can co-exist in the same SDO channel.

Abstract: A PALC panel is operated by driving a channel electrode to a positive voltage relative to the data drive electrode to initiate an AC discharge in the channel and thereafter maintaining a sufficient voltage between the channel electrodes to sustain a DC discharge in the channel.

Abstract: A method for controlling a digital oscilloscope locates a crossing level in an eye diagram (also including a crossing time), of a communications signal. The method includes the steps of locating the crossing time using a horizontal histogram box; and locating the crossing level using a vertical histogram box placed at a horizontal location substantially at the located crossing time.

Abstract: A deskew fixture has a multilayer circuit board from which pairs of mirrored signal launch contact extend from both sides of the circuit board. One pair of contacts is coupled to electrical ground and the other pair is connected via equal length, electromagnetically coupled strip lines to a signal source. Probe holders are mounted on the circuit boards to support measurement probes with the probing contacts of the measurement probes coupled to the signal launch contacts. Additional pairs of signal launch contacts may be provided with one pair receiving a positive signal from the signal source and another pair receiving a negative signal via equal length, electromagnetically coupled strip lines from the signal source for deskewing differential measurement probes.

Abstract: A network analyzer using time sequenced measurements has a pair of switches for isolating respective mixers from a local oscillator source to ease problems caused by direct leakage from the signal source. The signal source is set to a desired measurement frequency and a local oscillator is set to a desired frequency so that, when mixed, a desired IF frequency is achieved. The signal source output is applied to a return loss bridge, to which also is coupled a device under test, and to a reference channel mixer. A return loss signal from the return loss bridge is applied to a test channel mixer. The LO output is applied in a time sequence via an LO switch first to the reference channel mixer and then to the test channel mixer. An output switch couples the respective mixers to a processor in the same time sequence to provide sequential measurements of magnitude and phase from which reflection coefficients are derived for the device under test.

Abstract: A clock recovery system includes a source of a data signal having transitions, an injection-locked oscillator having a free-running frequency and generating a clock signal, and a free-running frequency adjustment circuit. The free running frequency adjustment circuit includes a transition density detector for detecting the density of the transitions in the data signal; a phase error detector for detecting the phase error between the clock signal and the data signal; and a correlator for adjusting the free-running frequency of the injection locked oscillator in response to the correlation between the detected transition density in the data signal and the phase error between the data signal and the local oscillator.

Abstract: An electrical standoff has a dielectric substrate with opposing horizontal surfaces and at least two opposing vertical end walls. A transmission structure having planar elements is formed on the at least one of the horizontal surfaces with the planar elements of the transmission structure extending to the two opposing vertical end walls. The electrical standoff is formed from a wafer of dielectric material having at least a first transmission structure formed thereon. A low temperature water soluble wax is applied over the transmission structure and a protective covering is placed over the water soluble wax. The wafer is sawn to form the electrical standoff with the electrical standoff having two opposing sawn vertical end walls intersecting the planar elements of the transmission structure. The protective covering and the low temperature water soluble wax are removed from the electrical standoff.

Abstract: A probe tip adapter for a measurement probe has at least a first electrically conductive element with a bore at one end and a probing contact formed on the other end. The bore of the electrically conductive element has an electrically conductive elastomer disposed therein having sufficient tensile strength, compression set, hardness, deflection force, elongation and percent recovery for repeatably securing the electrically conductive element to the probing tip of the measurement probe. The probing contact may be configured as a probing tip having a shaft that tapers at one end to a point and as a square pin adapter with a bore formed in the electrically conductive element that receives a spring contact. The probe tip adapter is useable with both single ended and differential measurement probes.

Abstract: A probe head holder for a measurement probe head has a probe head mount and a highly elastic, high hoop strength retention member that flexibly secures the measurement probe head to the probe head holder. The probe head mount has a first surface adapted to receive the measurement probe head and a second surface extending from the first surface having at least a first groove formed therein normal to the first surface. The retention member is positioned around the holder and the probe head with a portion of the retention member being disposed in the groove. The probe head holder may be attached to a probe arm of a probing station.

Abstract: An array of parallel spaced fiber segments is attached to the flat upper surface of a transparent plate. The transparent plate and the fiber segments preferably are made of glass, with the fiber segments bonded to the transparent plate with fused glass frit or by sintering under pressure. The plate and attached fiber segments suitably are embodied in the channel substrate for a plasma-addressed display device, such as a PALC panel.