Abstract: Peak capture circuitry for measuring a peak value of a waveform characterized by a first portion having a first rate of change and a second portion having a relatively faster rate of change. Peak stretching circuitry stretches a portion of the waveform as a function of time. Digital signal processing circuitry samples an output waveform of the peak stretching circuitry for determining the peak value. Thus, despite any steeply sloped portion, samples can be reliably taken throughout the waveform for calculation of peak value.

Abstract: Peak capture circuitry for measuring a peak value of a waveform characterized by a first portion having a first rate of change and a second portion having a relatively faster rate of change. Peak stretching circuitry stretches a portion of the waveform as a function of time. Digital signal processing circuitry samples an output waveform of the peak stretching circuitry for determining the peak value. Thus, despite any steeply sloped portion, samples can be reliably taken throughout the waveform for calculation of peak value.

Abstract: A digital engine analyzer has an oscilloscope display screen operable in single-trace and dual-trace modes and in live and freeze modes, and having signal pickup leads for respectively acquiring different input signal waveforms from the engine and digitizing them for storage and display. When the freeze mode is entered, the last-displayed screen display format is frozen, and can then be reconfigured by the user by altering one or more of the number of traces, the signal plotted on each trace, the engine sweep of each trace, the scale and the scale offset for each trace and, in the case of a cylinder sweep, the displayed cylinder. In dual trace screen display formats, the user can also select for display on trace 2 a waveform pattern selected from a stored library of patterns.

Abstract: A display control apparatus includes a display screen and a mouse and a processor coupled to the screen and mouse for displaying a mouse cursor and icons graphically representing switches, with each switch having assigned thereto a circular list of indicia respectively representing different switch options. If the mouse button is clicked on an icon the switch associated with the icon is activated and if the mouse button is held down while the cursor is on an activated icon the list of indicia assigned to the icon switch is scrolled through the icon while the cursor remains trapped in the icon. The display screen is incorporated in an engine analyzer which stores frames of digitized waveform data, the screen having a frame icon which indicates number in a decimal number, the number of the frame being displayed. When the cursor button is held down while the cursor is on the frame icon, vertical movements of the mouse will scroll the whole or integer part of the frame number through the icon window, i.e.

Abstract: An engine analyzer stores acquired cylinder waveform data in circular buffers respectively associated with the cylinders in accordance with cylinder selection by the user, with each buffer including a plurality of storage cells respectively storing data for individual firing cycles of the associated cylinder, and simultaneously displays the waveform for a, single selected cylinder on one trace of a display screen and waveforms for all cylinders for which data is stored on a second trace, so that data can be acquired and displayed from direct ignition engines with the use of a single pickup lead connected to selected cylinders one cylinder at a time. Various display modes are possible, including a frozen mode in which all stored waveform data may be reviewed and displayed.

Abstract: A digital engine analyzer includes an ADC which can become railed to clip an acquired waveform signal. The analyzer has a waveform display system which displays an indication of the rail level and the fact that a displayed waveform representation is clipped at the rail level. In one embodiment the rail level is displayed as a red line and the clipped portion of the waveform is displayed as a flat line substantially at the rail level. In another embodiment, the clipped portion of the waveform representation is displayed in red as a horizontal line at the rail level while the remainder of the waveform representation is displayed in green, and the rail level is otherwise not displayed.

Abstract: An engine analyzer has an oscilloscope screen display operable with a fixed-time sweep. The analyzer includes a data acquisition system for digitizing analog input waveforms and a memory for storing the digitized waveform data, the analyzer including sensors for detecting each cylinder firing and the firing of the no. 1 cylinder for identification of the cylinders. A processor includes trigger means for controlling the triggering of the oscilloscope display at a trigger point which corresponds to the firing of a trigger cylinder which is selectable by the user, so that the displayed waveform data begins with the stored data for the selected trigger cylinder. The user can also selectively vary the location of the trigger point on the screen display.

Abstract: An engine analyzer having a dual-trace digital oscilloscope includes a memory for storing a library of digitized waveform patterns, the patterns being stored together with identifying data for each pattern and lists of groups of patterns respectively corresponding to different vehicles and/or engines. The analyzer includes a user interface for inputting identifying information relating to the vehicle under test, a waveform acquisition module and a central processor for cooperation with the memory and the oscilloscope for acquiring, digitizing and storing an analog input waveform from the vehicle engine and displaying it on a first trace of the scope in accordance with selected display parameters.

Abstract: An engine analyzer having a dual-trace digital oscilloscope display provides a discrete waveform plot area for each trace and displays in each plot area a cursor array which may selectively include one or two vertical-line cursors which can be selectively moved one at a time horizontally along the plot area. The movements of the two cursor arrays can selectively be either synchronized or unsynchronized. The scope provides alphanumeric indications of the position of each cursor, the waveform value at the point where each cursor intersects the waveform. When two cursors are displayed on a trace the scope provides alphanumeric indications of the distance between the cursors and the difference between the waveform values at the points where the cursors intersect the waveform.

Abstract: An engine analyzer having a dual-trace digital oscilloscope includes a memory for storing a library of digitized waveform patterns, the patterns being stored together with identifying data for each pattern and lists of groups of patterns respectively corresponding to different vehicles and/or engines. The analyzer includes a user interface for inputting identifying information relating to the vehicle under test, a waveform acquisition module and a central processor for cooperation with the memory and the oscilloscope for acquiring, digitizing and storing an analog input waveform from the vehicle engine and displaying it on a first trace of the scope in accordance with selected display parameters.

Abstract: A data acquisition device permits plotting of cylinder firing cycles, of varying-frequency, on a fixed-plot area of a CRT screen. Each cylinder firing cycle is sampled, at a constant sample rate, and consecutive sets of sample points, each containing a fixed number of sample points, is generated. On the basis of a unique data reduction technique triggered after the collection of each consecutive sample-point set, certain of the sample points considered superfluous are deleted from the set and the remaining appended to a temporary buffer. The sample-points in the temporary buffer further undergo reduction of the sample points when certain conditions occur, such as buffer full, at which time certain ones are discarded and others are kept. At the end of a cylinder firing cycle, the remaining points are further reduced and a final-set is generated, representative of a full cylinder firing waveform, consisting of sample points equal in number to the plot-width of the CRT screen.

Abstract: An engine analyzer with a digital oscilloscope display includes a processor for controlling the acquisition and display of a high-voltage secondary ignition signal waveform with the use of only a single high-voltage reactive pickup probe, the waveform being displayed with a fixed-time sweep and either auto or signal triggering. The system provides for user selection of the sweep and trigger modes.

Abstract: A method and apparatus are provided for printing a color computer screen display on a monochrome printer by establishing for the screen display a print filter including a set of filter blocks for controlling the printing of the screen display, wherein each filter block designates a filter realm area on the screen in which the filter block is active and a filter color acted on by the filter block and a filter type instructing the printer to either print or not print pixels which lie within the realm area of the block and have a color which matches the filter color of the block. Plural print filters can be established for a screen display or display components thereof and each print filter is enabled when the associated screen display or display component is displayed on the screen. For any portion of a screen display or display component which lies within overlapping realm areas of different print filters, the last-enabled print filter governs the printing.

Abstract: An engine analyzer has a dual-trace display screen, a waveform acquisition means for obtaining analog waveforms from an associated engine and digitizing them, a memory for storing digitized waveform data and a processor for controlling the operation of the memory and the display. The display is operable in live and freeze modes. The displays on the two traces of the display screen are normally synchronized but, in freeze display mode, the user may selectively deactivate the synchronization.

Abstract: An engine analyzer for plotting engine cylinder firing or spark voltage information, corresponding to distinct points of a cylinder firing waveform, in histograph form to assist in identifying a cylinder-misfire condition. In an illustrative embodiment, two traces are provided. The lower trace depicts a histograph, representative of the firing or spark voltage and engine speed of each cylinder over successive engine cycles. The histograph consists of successive pairs of adjacent, vertical histo-bars, each pair representing voltage and engine speed for a single cylinder. The first histo-bar in each pair represents the spark or firing voltage for a given cylinder and the second histo-bar represents the instantaneous engine speed measured over the duration of the given cylinder. The vertical histo-bar pairs are plotted sequentially from left to right, representing successive cylinder firings.