Abstract: A digital engine analyzer has an oscilloscope display and is controlled by microprocessors operating under menu-driven stored program control. The analyzer receives analog input signals from an engine being analyzed, digitizes the signals, captures the digital peak ignition voltage values for each cylinder and stores only these values for each cylinder over a number of successive engine cycles, and then simultaneously displays all the stored values for any one cylinder over a number of engine cycles to provide a historical display. Each peak value is stored twice and displayed twice to provide width to the value display and effectively produce a bar graph-type display.

Abstract: A digital engine analyzer has an oscilloscope display and is controlled by microprocessors operating under menu-driven stored program control. The analyzer receives analog input signals from an engine being analyzed. The analyzer is provided with a scanner interface, so that a scanner designed to read data from a vehicle on-board computer, can transfer this data to the analyzer for display on the analyzer oscilloscope. The analyzer processor, when operating in the scanner interface mode, operates under stored program control to reconfigure analyzer keyboard and soft key functions to duplicate scanner control functions, so that the scanner control functions can be effected from the analyzer.

Abstract: A waveform measuring device comprising an A/D converter for converting an input signal into a digital signal, a memory for storing output data from the A/D converter, a first trigger condition detecting unit for detecting a present input signal meeting a first trigger condition, a second trigger condition detecting unit for detecting a past input signal of a desired time which is remote from the present time and meeting a second trigger condition, and a trigger signal generating unit for generating a trigger signal when the trigger conditions of the first and second trigger condition detecting units are satisfied. The waveform of the input signal corresponding to a desired interval is displayed in accordance with the trigger signal from the trigger signal generating unit. The input signal to the second trigger condition detecting unit is given without reading it out of the memory.

Abstract: A system for simultaneously probing an electrical test circuit while remotely controlling the test equipment used to measure the probing. The probing is performed by the use of an electrical test probe of the type utilized with oscilloscopes or the like. Incorporated within the probe are switches adapted to detecting both lateral and longitudinal pressures exerted by the probe user. The lateral pressure is applied to the lower portion of the probe and depending upon the direction of the pressure causes a cursor displayed on the test equipment to move. The user moves the displayed cursor to the desired position, which position corresponds to a function or option of the test instrument. Upon selection, the user exerts a longitudinal force upon the probe, which force is detected by the probe and activates the selected function or option on the test instrument.

Abstract: A waveform measuring device comprising an A/D converter for converting an input signal into a digital signal, a memory storing output data from the A/D converter, a first trigger condition detecting unit for detecting a present input signal meeting a first trigger condition, a second trigger condition detecting unit for detecting a past input signal of a desired time which is remote from the present time and meeting a second trigger condition, and a trigger signal generating unit for generating a trigger signal when the trigger conditions of the first and second trigger condition detecting units are satisfied. The waveform of the input signal corresponding to a desired interval is displayed in accordance with the trigger signal from the trigger signal generating unit. The input signal to the second trigger condition detecting unit is given without reading it out of the memory.

Abstract: It is known to provide measuring instruments, such as oscilloscopes or other measuring instruments, with analog adjustment elements for adjusting various parameters, such as the horizontal and vertical position of a signal (s1, s2) to be displayed, of trigger devices, etc. A digital measuring instrument is disclosed having digital adjustment elements in which the reaction behaviour of the parameters to be set substantially corresponds to that of a measuring instrument with analog adjustment elements. For this purpose, the adjustment elements are constructed as rotatable pulse generators and the measuring instrument is provided with a pulse processing device by which the pulse duration (T, T') of the pulses generators is determined. Thus independently of the rotational speed, a parameter reaction behaviour can be set by this device which results in a natural reaction behavior similar to that of analog adjustment elements.

Abstract: A signal acquisition and sampling system mounted in an oscilloscope probe includes an input buffer amplifier (30) featuring shunt feedback, offset capability, input bias current compensation, and very low input capacitance. Signal sampling is accomplished by a cascaded pair of differential sampling bridges including a fast track-and-hold stage (40) followed by a slow track-and-hold stage (50). The differential configuration of the bridges features common mode rejection of strobe signal coupling into the signal path and reduces aberrations and voltage droop. The fast track-and-hold stage features Schottky diode switching bridges (42A) and (42B), low value storage capacitors (44A) and (44B), thereby resulting in a fast tracking time. The slow track-and-hold stage features low-leakage diode-connected transistor switching bridges (52A) and (52B) and a FET buffer stage, thereby resulting in fast acquisition of the fast stage output and long hold time for quantization of the sample.

Abstract: A method and circuit for triggering an electronic instrument only once during a period of an input signal having multiple triggering events during that period. A signal applied to an electronic instrument, such as an oscilloscope, is acquired. Qualified triggering events occurring on the acquired signal are identified. A selected one of the qualified triggering events during the period of the applied signal causes a trigger signal output to occur, while other qualified triggering events are ignored. In the preferred embodiment a triggering event is qualified by a first comparator that compares the input signal to a first reference level and produces a predetermined logic level output if the input signal bears a predetermined relationship to the reference level. When a qualified triggering event occurs, a buffer amplifier applies the predetermined logic level to charge a capacitor, which thereafter stores some energy from the input signal and applies it to a comparator for a predetermined period of time.

Abstract: An apparatus and method for digitizing a repetitive waveform using an analog oscilloscope uses a successive approximation technique. For each sample point on the repetitive waveform a digitizing level is compared with the repetitive waveform at that sample point, and the digitizing level is adjusted until it essentially equals the magnitude of the repetitive waveform at that point. The particular sample point is determined by comparing a delay level with a ramp signal that starts from an initial fixed trigger point on the repetitive waveform. Each point is digitized in this manner in one of three modes. The first mode samples the same point on successive iterations of the waveform until that point is digitized, and then the next point is digitized. The second mode samples each point once per iteration of the waveform by stepping the delay level n times during each iteration, and adjusting the digitizing level individually for each sample point until the digitization is complete.

Abstract: An oscilloscope provides adjustable control of the reference voltage level to the trigger comparator to calibrate the trigger for both gain and offset. An internal computer in the oscilloscope provides a digital input value to a gain digital-to-analog converter (DAC) the analog output of which is provided to the reference input of a level DAC. The level DAC also receives digital input from the control computer and provides its analog output to the reference input of the trigger channel comparator. The digital data value provided to the gain DAC determines the relative gain of the output signal from the level DAC.

Abstract: Circuits for increasing throughput in random repetitive signal acquisition systems that use triggers. The circuits allow the random repetitive signal acquisition systems to terminate an acquisition only when there is a high probability that usable samples have reached the systems. The circuits comprise logic elements for producing a qualifier signal having at least two input ports. A first delay element is coupled to a first input of the logic element for introducing a first delay in a sample signal, thereby producing a first delayed sample signal for setting the logic element and enabling the qualifier signal. A second delay element is coupled to a second input port of the logic element for introducing a second delay in the sample signal, thereby producing a second delayed sample signal for resetting the logic element and disabling the qualifier signal. The qualifying signal qualifies a trigger signal produced by trigger circuitry in the random repetitive signal acquisition system.

Abstract: A measuring instrument having a programmable time base circuit including a digitally adjustable integrator for generating a plurality of sawtooth voltages for the different operational states of a CRT display apparatus. The measuring instrument has an automatic calibration procedure for calibrating the various time base settings. A microcontroller drives the digitally adjustable integrator during calibration of the measuring instrument so as to calibrate the time base circuit for each operational state. A detection circuit detects whether the time base circuit is calibrated and provides a status signal to cause a digital memory in the microcontroller to store calibration values determined in the calibration procedure. During normal operation of the measuring instrument, the microcontroller drives the integrator of the time base circuit using the stored calibration values for the corresponding operational states.

Abstract: A sampling signal analyzer in which the frequency of an input signal to be measured is initially ascertained, an appropriate sampling frequency is then determined, data needed to reconstruct the wave form of the input signal is acquired, and the input signal wave shape is reconstructed with a calibrated time axis and preferably displayed. The sampling signal analyzer synthesizes a sampler drive signal to enable continuous sampling of the input signal and therefore has the advantage over known data sampling signal measurement instruments that it is not triggered directly in response to the level of the input signal to be measured. Instead, sample timing is based on numerical analysis of the intermediate frequency (IF) signal produced by the sampler. The IF frequency can be an arbitrarily low frequency, which allows digitizing and digital signal processing for aligning measurement data from sweep to sweep with precision.

Abstract: A very fast autoscale feature can be implemented in a digitizing oscilloscope by using dedicated peak detector hardward [14] capable of operating at the maximum sampling rate of the A/D converter [12] to determine the minimum and maximum values of said input signal, in combination with a trigger counter [24, 26] to count the number of trigger events in the analog input signal. While in the autoscale mode, the oscilloscope microprocessor [22] can then set the appropriate scale and offset for the Y-axis of the display as a function of the maximum and minimum values determined by the peak detector [14] and set the sweep rate as a function of the count provided by the tripper counter [26].

Abstract: A waveform measuring device comprising an A/D converter for converting an input signal into a digital signal, a memory for storing output data from the A/D converter, a first trigger condition detecting unit for detecting a present input signal meeting a first trigger condition, a second trigger condition detecting unit for detecting a past input signal of a desired time which is remote from the present time and meeting a second trigger condition, and a trigger signal generating unit for generating a trigger signal when the trigger conditions of the first and second trigger condition detecting units are satisfied. The waveform of the input signal corresponding to a desired interval is displayed in accordance with the trigger signal from the trigger signal generating unit. The input signal to the second trigger condition detecting unit is given without reading it out of the memory.

Abstract: A sync separator separates vertical, field and horizontal synchronization signals from a video signal processed by a circuit under test which exhibits an artifact in the video. The cause of the artifact in the circuit under test is to be located using an oscilloscope. A line select circuit includes a delay responsive to the separated vertical and field signals for generating a marker signal and for positioning the marker signal via observation of the display produced by video signal under test. A trigger signal and marker generator refines the marker signal by causing the boundaries of the marker signal to coincide with corresponding horizontal sync pulses and produces an oscilloscope trigger signal having a transition which is formed by one of those boundaries. A combiner circuit combines the refined marker signal with the video signal under test for display so that the marker signal via the delay can be positioned on a region of interest in the video display.

Abstract: A method for examining an input signal and setting a modulation domain measuring instrument to a state which will produce a measurement and a stable, centered, properly scaled display of the signal, automatically. After finding the 50 percent voltage threshold of the input signal, an iterative process determines the minimum and maximum input frequency, then checks the ratio of these two frequencies against instruments limits, and adjusts the display values, if necessary to show only the higher frequencies. The method then varies the measurement parameters to seek the best frequency resolution while maintaining the measurement and display of frequency modulation. The display frequency scale is set to display the signal in the center half of the display, using values with no more than two significant digits for the center and span. The time scale is set to display a selected number of modulation cycles.

Abstract: A relay device having a relay element mounted on a circuit board, the relay element having a pair of contacts which are closed and electrically conducted by a control signal of a first level and opened by the control signal of a second level to form a contact gap; an LED for emitting light toward the contact gap; a phototransistor for receiving light from the LED, the phototransistor not receiving the light while the pair of contacts are closed, and receiving the light passing through the contact gap while the pair of contacts are opened; and a checker circuit for checking if the relay device operates normally or abnormally in accordance with the relationship between an output from the phototransistor and the level of the control signal.

Abstract: A device to assist in setting up the pitch, roll, yaw and standoff of a read head relative to a scale, so as to improve the quadrature relationship of its outputs. Two superimposed Lissajous figures are produced on an oscilloscope screen. One of these figures is a rotation or reflection of the other. The read head is adjusted until the Lissajous figures coincide. Simpler, less accurate arrangements are also described, in which a variable DC output signal is produced which represents the radius of a hypothetical Lissajous derivable from the signals. The read head is then adjusted to give a constant DC output, representing a constant Lissajous radius.

Abstract: A method and apparatus prevents unwanted synchronization from obstructing a data acquisition instrument operator's view of N multiplexed signals synchronized to a high speed system clock being used to trigger an instrument through a prescaler with a fixed prescaling factor M, where N and M are related by a common factor. During a time while the instrument, for example, an oscilloscope, is ignoring trigger input information, a desynchronizing signal is applied to the prescaler, causing it to miss a random number of counts or causing it to count incorrectly. Thus, when the oscilloscope resumes triggering it is likely to be synchronized to a different combination of the multiplexed signals. This technique can be applied to individual data points or to records containing a number of data points.

Abstract: A method and apparatus performs time-interval to voltage conversion immediately and continuously allowing timing variations to be viewed and correlated with other voltage signals displayed on an oscilloscope. A calibration output assists in calibrating the vertical gain and offset of the oscilloscope. An automatic setup software routine finds suitable resolution and offset settings. The method includes the steps of selecting the type of time-interval to be measured, scaling the counting of a clock signal appropriately, offsetting the counting means as desired, counting the number of clock signals that occur during every selected time-interval, limiting the counted results to a preselected range, and converting the counted results to an analog voltage for display by an oscilloscope.

Abstract: An automatic anomalous event detection method uses a pair of counters to count the occurrence of main triggers simultaneously with the occurrence of advanced triggers indicative of anomalous events as defined by an operator. The anomalous events may be defined as either time or voltage qualified events that occur at a much lower rate than the repetition rate of an input analog signal being measured. When the main trigger counter reaches a maximum count, the count of the advanced trigger counter is compared with a range greater than zero to less than the maximum count modified by an operator specified divider. If the advance trigger count is within the range, then an anomalous event is detected and the next advanced trigger signal causes a portion of the input analog signal to be acquired for storage in a waveform memory and subsequent display of the anomalous event.

Abstract: A frequency conversion section sweeps an object signal within a desired measurement frequency range, thereby frequency-converting the object signal. A peak detector detects a peak of an output from the frequency converting section. A measurement detector measures and detects the output from the frequency conversion section simultaneously with the peak detection by the peak detector. The measurement detector has an output characteristic lower than an output characteristic of the peak detector. A display displays an output from the peak detector and an output from the measurement detector on a single display screen, in synchronism with the sweeping by the frequency conversion section, with these outputs of the peak detector and the measurement detector being plotted along an axis representative of frequencies. In another mode of the invention, an alarm device indicates the fact that an output from the peak detector has exceeded a predetermined allowable limit level.

Abstract: A method and apparatus is disclosed to prevent aliasing while sampling a low frequency analog input signal. A clock produces a series of electrical pulses at a predetermined frequency F.sub.o. An analog-to-digital ("A/D") converter samples the input signal at each clock pulse. Sample selection means randomly select one clock pulse from each successive series of N clock pulses, where N is a predetermined integer much greater than one. A memory receives the digital output values from the A/D converter, but only stores the current digital output value at each selected clock pulse. As a result, the long-term average frequency of sample storage is substantially equal to F.sub.o /N, but the interval between successive samples is random (i.e. the interval between successive samples is typically not equal to N clock pulses).

Abstract: Waveform digitization techniques and apparatus are shown. An input waveform is shown on a display device such as an oscilloscope as a high density sequence of either horizontal or vertical line segments which track the overall shape of the waveform. This digitization technique includes determining minimum and maximum values of the input waveform and storing these as sets. As these minimum and maximum samples are collected, each sample is compared with a previous minimum and maximum value that had been found during a current line period. The minimum and maximum values for the total line period are stored in a memory. Under processor control these sets of minimum and maximum samples are displayed on a visual display device such as an oscilloscope.

Abstract: A method facilitates the display of a filtered signal which represents the variation of light intensity in a processing chamber over time. The filtered signal filters out the effects of a magnetic field which causes plasma within the processing chamber to rotate. The magnetic field is generated by a signal with a period T. Light intensity within the process chamber is detected to produce a voltage signal with a voltage amplitude which varies based on the light intensity within the process chamber. The voltage amplitude of the voltage signal is digitally sampled at a sampling interval to obtain sample values. Running averages of a preselected number of sample values are calculated. The period T is set equal to the preselected number of sample values times the sampling interval times an integer. For each newly displayed running average, a rectangular box may be superimposed over a graph of the running averages in order to graphically display changes in slope.

Abstract: Display section displays, on a screen, a zone marker for indicating, on a wide-band spectrum display area, that part of a wide-band spectrum which corresponds to a selected narrow-band spectrum to be displayed, and the wide-band spectrum, as well as said narrow-band spectrum which has been enlarged. First setting section changes a center frequency or a band width of said displayed narrow-band spectrum, in accordance with the change of the position or width of the zone marker. Second setting section cooperating with the first setting section changes the position or width of the zone marker in accordance with the movement of the center frequency or band width of the displayed narrow-band spectrum. Control section for controlling a measurement resolution and a sweep time in accordance with the magnitude of the displayed spectrum, so as to satisfy the formula:sweep time.gtoreq.band width/(measurement resolution).sup.2 .multidot.Kwhere K=a constant.

Abstract: A method for examining an input signal and setting a modulation domain measuring instrument to a state which will produce a measurement and a stable, centered, properly scaled display of the signal, automatically. After finding the 50 percent voltage threshold of the input signal, an iterative process determines the minimum and maximum input frequency, then checks the ratio of these two frequencies against instruments limits, and adjusts the display values, if necessary to show only the higher frequencies. The method then varies the measurement parameters to seek the best frequency resolution while maintaining the measurement and display of frequency modulation. The display frequency scale is set to display the signal in the center half of the display, using values with no more than two significant digits for the center and span. The time scale is set to display a selected number of modulation cycles.

Abstract: Disclosed is a test system having an arbitrary waveform generator, a comparator, and a test controller to analyze the arbitrary signal output from a device under test. The output of the device under test is connected to one input of the comparator and the output of the arbitrary waveform generator is connected to the other input of the comparator. The test controller stimulates the device under test, causing it to perform a function, and stimulates the arbitrary waveform generator, causing it to generate a limit envelope signal. The output of the comparator is continuously monitored by the test controller to determine whether the signal output of the device under test exceeds the limit envelope created by the arbitrary waveform generator.

Abstract: A method for simulating an analog display in a digital display spectrum analyzer (or other digital display test instrument) comprises the steps of defining a plurality, N, of traces of the signal to be displayed, assigning coordinate values to points along each trace, and plotting and simultaneously displaying each of the N traces by illuminating corresponding pixel locations on the CRT as indicated by the assigned coordinate values. The method permits effective simulation of trace persistence as commonly found in analog display test instruments. According to one embodiment of the invention, a color graphics controller/color CRT may be provided, in which case gray scales may be generated and displayed to simulate variations in intensity levels as commonly found in traces plotted on analog display test instruments. An apparatus for practicing the method is also disclosed.

Abstract: A triggering system (1) comprises a trigger device (4) to which a trigger input signal is supplied from an input (2) via parallel signal paths (6, 7, 8). One signal path (6) may be a direct connection, while the other signal paths (7, 8) include frequency division devices (10, 13). The signal paths (6, 7, 8) are selectively switched between the input and the trigger device under the control of frequency-dependent switching devices (16, 21) depending on the frequency of a signal obtained from an input signal at the input (2) of the triggering system. As a result, the useful frequency range of the triggering system (1) is extended up to much higher frequencies than would be determined solely by the bandwidth of the trigger device.

Abstract: A digital picture display device in which, due to a location-dependent, determined brightness drive of pixels in a picture formed line and field-sequentially, it is possible to obtain an oscilloscopic image in the form of a waveform profile on a display screen (TV, OSC). A digital signal comparison circuit (COMP) having a first input (I1) for receiving location information in the form of an actual line number (L-act) and a second input (I2) for receiving from a line buffer circuit (W-buf) digital values of the waveform profile to be displayed. The signal comparison circuit produces a binary drive signal (BDS) at its output.

Abstract: A system for time-resolving ultra-short electrical waveforms of up to a few hundred gigahertz bandwidth is presented. The system utilizes a fast electro-optic modulator capable of subpicosecond responsivity. A CW (continuous wave) laser is used to probe the change in birefringence resulting in the modulator due to an induced electric field. The rapid change in the transmitted optical signal due to an equally rapid changing electric field (picosecond pulse) is then detected and temporally dispersed using a picosecond resolution streak camera. The modulator operates in a region close to minimum transmission where the average optical power is below the damage threshold for the photocathode of the streak camera and where small electrical signals can significantly modulate the transmitted beam. The system can be used in either sampling mode where the modulation and subsequent detection are repeated and the data accumulated at repetition rates as high as 100 MHz or in single shot mode.

Abstract: A data processing system for processing measurement instrument data is disclosed having a processor for digitally manipulating the measurement instrument data, a memory for storing the digitally manipulated data, and a display. In one preferred embodiment, the display simultaneously displays side by side two traces of the data, so as to provide two independent side by side displays. The displays can be either real time or can be recovered from memory, and a plotter can be used to produce hard copy. In another embodiment, the display provides a trace of the data with a plurality of markers. The user can then choose one of the markers as a reference and the processor will automatically provide the value of the trace at each of the other markers relative to the value of the reference marker. In another embodiment, the system includes a keyboard having a value key for entering into the processor the current value of a marker on the data trace.

Abstract: Calibrated voltage cursors with respect to an input waveform signal are produced for display with the input waveform signal by injecting the cursor signals into the signal path prior to any gain stages in the signal path.

Abstract: A digital oscilloscope displays two waveforms on the CRT screen, a scroll bar waveform which is an abstracted representation of the full waveform data stored in memory and a generally expanded portion of the full waveform data in the memory. The portion of the full waveform that is displayed is selected by the operator by positioning cursor brackets along the abstracted scroll bar waveform to define a region of interest between the brackets. The region of interest so selected is displayed in expanded form showing all data points in the memory for the portion of the waveform being displayed. Creation of the abstracted scroll bar waveform is obtained by examining the waveform data in sections of equal time length and determining whether any data in each section falls within a series of predetermined ranges. The scroll bar waveform is formed of a series of columns of pixels equal in number to the number of sections of memory data, and having a number of pixels in each column equal to the number of data ranges.

Abstract: A device for simultaneously displaying unrelated signals processes the signals separately prior to inputting them to a multiplexer. Under control of a microprocessor the multiplexer. Under control of a microprocessor the multiplexer switches between the processed signals to alternately pass the signals to the deflection circuits of an X-X display device at a rate which does not interfere with other frequencies used in the environment where the device is used.

Abstract: In a frequency specturm analyzer system, horizontal interconnect between RF and display functions is eliminated by introducing a sync pulse on the vertical interconnect.

Abstract: Waveform digitization techniques and apparatus are shown. An input waveform is shown on a display device such as an oscilloscope as a high density sequence of either horizontal or vertical line segments which track the overall shape of the waveform. This digitization technique includes determining minimum and maximum values of the input waveform and storing these as sets. As these minimum and maximum samples are collected, each sample is compared with a previous minimum and maximum value that had been found during a current line period. The minimum and maximum values for the total line period are stored in a memory. Under processor control these sets of minimum and maximum samples are displayed on a visual display device such as an oscilloscope.

Abstract: A multi-standard vide option for an oscilloscope detects whether an input video signal has a bi-level or a tri-level horizontal sync pulse from a composite sync signal derived from the input video signal. A ramp signal is generated from the horizontal sync pulse having a slope of one polarity that changes to a slope of the opposite polarity when the horizontal sync pulse is tri-level. For a bi-level horizontal sync pulse the ramp is limited in magnitude and rapidly discharged at the end of the horizontal sync pulse. A digital output signal is generated from the ramp signal and has a width equal to the width of the horizontal sync pulse regardless whether it is bi-level or tri-level. From the type of horizontal sync pulse and the width or the number of lines per frame, a video standard is determined and is subsequently used to determine field identification and to automatically set up the horizontal sweep of the oscilloscope according to a selected video setup.

Abstract: An oscilloscope includes a digitizing camera mounted thereon for recording waveforms on the oscilloscope screen. The digitized signals representing the waveforms are stored in the computer. In the calibration process a plurality of baselines substantially equidistant from one another are scanned on the screen and thereafter a plurality of sine waves are scanned. The phase differences between each sine wave and an associated ideal sine wave are determined and are used to create a map which associates each point on a waveform of interest appearing on the oscillosope screen with a time value that corrects for nonlinearities in the horizontal axis which are injected by the optics, nonlinear voltages, etc. Another map is created utilizing the baseline scan which corrects for such nonlinearities in the vertical axis.

Abstract: Adjustable electronic graticules for measuring waveform distortions are generated from operator inputs indicating a measurement mode and a scale factor. A template of a graticule for the measurement mode in the form of a display list of move and draw instructions is scaled by the scale factor and a measurement value is computed from the scale factor and the instrument units per division setup. The graticule and measurement value are stored as a modified display list. A readout engine interprets the modified display list and produces electrical signals for drawing the graticule and measurement value on a display monitor. The electrical signals are combined with the waveform for display on the display monitor. The operator varies the scale factor until the displayed graticule touches the waveform at a measurement point, and the measurement value is accordingly displayed.

Abstract: Disclosed is a probability density histogram display for a digital oscilloscope which shows a probability density histogram display of an input signal waveform alongside the conventional voltage-versus-time time-domain display of the waveform. The histogram shows the relative frequency of occurrence of voltage amplitude levels of the waveform. The histogram is optional and shown simultaneously with the time-domain display of the waveform.

Abstract: A visual indication of the location and duration of a measurement gate relative to the signal being measured is provided on a display. In response to a start gate signal measurements are initiated and a predetermined change is effected in the normally displayed visual indication of the signal being measured. In response to a gate close indication, measurements are terminated and the normally displayed visual indication is resumed. The normal and changed visual indications are effected by a display control signal produced by summing the signal to be measured and an event gate signal at a point in the circuit near where the event gate signal is generated.

Abstract: The electrical signal observing device measures the electrical signal by applying the electrical signal to be measured to an optical amplifier in order to modulate a short pulse light train directed through the electrical amplifier. The electrical signal to be measured acts as a gain control for the optical amplifier. The photodetector detects the output of the optical amplifier and applies a resultant electrical signal to an integrator circuit after which the signal is displayed. The signal may be displayed in a time base fashion using a sweep generated by a delay system of the short pulse light train.

Abstract: Provided is a an overlaid digital signal waveform display for a logic analyzer. The present invention allows the logic analyzer user to overlay, that is superimpose, individual digital waveforms within a functional group of waveforms onto each other so that all the waveform transitions within the group appear at one level across the display screen of the logic analyzer. Thus, all waveforms within a functional group, such as all the address line waveforms of an address bus, can be overlaid onto each other. In addition, individual waveforms within the group can be shown isolated from the overlaid group.

Abstract: An operation display method and apparatus for variables of an oscilloscope including a rotary-push mechanism connected with a rotary knob is disclosed. When the rotary knob is rotated clockwise a little, a right directional arrow is displayed on a CRT. Then e.g. a cursor is shifted to the right on the CRT by a division every pushing the rotary knob. When the rotary knob is rotated clockwise or counterclockwise, the cursor is shifted a little to the right or the left. When the knob is rotated counterclockwise in the precise adjustment, a left directional arrow is displayed on the CRT. Then the cursor can shifted to the left on the CRT by a division every pushing the knob. Other variables can be operated in the same manner.

Abstract: A windowed portion of a displayed waveform under test, typically from an oscilloscope display, is simultaneously displayed at a higher resolution by using a software program in conjunction with the existing timebase circuit rather than using a second timebase circuit. The software uses the resolution of the interpolators (a stretcher circuit which uses capacitors to hold acquire a charge and measure the amount of time necessary to slowly discharge the circuit) to carry through all the plotting of points to a first and second display.

Abstract: A voltage detecting device using an electro-optical material with a refractive index that is changed by a voltage at a part of an object comprising a light source, an electro-optical material for changing the optical path of the light beam from the light source in accordance with the refractive index of the electro-optical material, and a streak camera to display on a Phosphor screen an image of the voltage over time at a part of the object.

Abstract: Provided is an oscilloscope-like user-interface for a logic analyzer. The oscilloscope-like user-interface simplifies user control of the logic analyzer. The oscilloscope-like user-interface substitutes two oscilloscope-like controls (seconds-per-division and delay) for six logic analyzer controls (sample-period, magnification, magnify-about, magnify-about marker-movement, start/center/end, and delay-from-trigger). The result of the substitution is a logic analyzer which is operable with oscilloscope-like controls and which does not require user understanding of the logic analyzer's sampling hardware for effective user operation.