Abstract: An apparatus and method for inverting a color display on a dark background to produce a display on a substantially white background suitable for printing, includes the element of maintaining the same apparent relative intensities in both the LCD display on a dark background and the hardcopy displayed on a light background. The apparatus includes a memory including a first palette for the LCD display, a second palette for the hardcopy display, and a look-up table. A controller accesses the first and second palettes and look-up table for converting display data from LCD data to color-inverted printer data.

Abstract: A trigger delay compensation arrangement for use in a digital storage oscilloscope, includes a trigger circuit for receiving a TRIGGER OUT signal generated from a logic analyzer in response to a logic analyzer trigger event signal, for starting a post trigger counter. It also includes a data entry circuitry for entering data input by a user, the data being representative of a delay between a reception of the logic analyzer trigger event signal and the generation of the TRIGGER OUT signal by the logic analyzer. A post trigger counter stops an acquisition of signal data upon expiration of a count of the post trigger counter. A controller, coupled to the data entry circuitry and to the post trigger counter receives the delay representative data, and adjusts the count of the post trigger counter in a direction to compensate for the delay.

Abstract: A new oscilloscope design improves the processing of acquired voltage-versus-time data through the efficient high speed acquisition and rasterization of such data into a form that includes multiple-bits-per-pixel intensity information. The multi-bit-per-pixel variable intensity rasterizer is optimized for maximum throughput and most efficient use of memory bandwidth. In the presence of faltering trigger rates, rasterization interruption provides a high probability of capturing the data associated with the slow triggers. Circuitry is provided to compensate for acquisition time and amplitude non-linearities. Many-bits-per-pixel intensity information is mapped into a fewer-bits-per-pixel format by a controllable transfer function that provides multiple viewing capabilities for the operator. Another mode of operation emphasizes infrequent events over commonly occurring ones using variations in brightness or color.

Abstract: A circuit for detecting and automatically responding to ground faults. A passive protection PTC resistor is coupled in series with an active protection switch, the active protection switch being controlled by a control circuit to open the switch when excess current is detected to be flowing in the common path of one of the channels. Floating and grounded versions are described.

Abstract: An apparatus and method useful in a test and measurement instrument for selecting a particular television field for display, determines the television system standard from the input signal, uses the standard selection to determine the time for one field, and multiplies the field rate by an operator-supplied number of fields to calculate the required holdoff time. The subject invention relieves the operator from turning the holdoff control multiple times, and also relieves the operator from having to calculate the time delays for any of one to seven fields of holdoff (in the case of a PAL signal).

Abstract: A raster scan digital signal acquisition and waveform display instrument displays a dot representing a signal event with a color parameter in accordance with the value of a corresponding data word stored in a raster scan memory. A user interface control element supplies a single color parameter control value from which multiple independent control values for influencing the values of the data words stored in the raster scan memory in response to the single color parameter control value are generated.

Abstract: A circuit for use in a DMM utilizes an auxiliary A/D converter to measure the battery voltage of the DMM and displays the result on the LCD display screen of the DMM. The user receives a numeric indication of the battery voltage measured, rather than a simple good/bad or bar graph indication. The voltage measured provides the user with a quantitative indication which allows the user to determine how close the battery is to being exhausted. Thus, the user can be made aware of a weakened state of the battery before operation of a backlight further drains the battery to an unacceptably low level.

Abstract: An apparatus and method useful in a test and measurement instrument for simultaneously adjusting both contrast and brightness via a single knob employs a family of modified gamma curves each having multiple breakpoints for mapping multiple-byte pixel intensity words into a multi-bit pixel intensity display control word. A single user-operable intensity control accomplishes selection of a particular gamma curve of the family of gamma curves, and causes the simultaneous adjustment of both contrast and brightness.

Abstract: A new oscilloscope design improves the processing of acquired voltage-versus-time data through the efficient high speed acquisition and rasterization of such data into a form that includes multiple-bits-per-pixel intensity information. The multi-bit-per-pixel variable intensity rasterizer is optimized for maximum throughput and most efficient use of memory bandwidth. In the presence of faltering trigger rates, rasterization interruption provides a high probability of capturing the data associated with the slow triggers. Circuitry is provided to compensate for acquisition time and amplitude non-linearities. Many-bits-per-pixel intensity information is mapped into a fewer-bits-per-pixel format by a controllable transfer function that provides multiple viewing capabilities for the operator. Another mode of operation emphasizes infrequent events over commonly occurring ones using variations in brightness or color.

Abstract: A simplified user interface for an electronic test and measurement device comprises an arrangement of a segmented LCD device and a plurality of keys used to implement a softkey system, in combination with a single AMPs input connector and a rotary selector having only a single position for each basic kind of parameter to be measured. The segmented LCD device includes, at each location adjacent to a key, a plurality of segments representing a vertically-arranged list of functions to be controlled. In one embodiment of the invention, the housing of the electronic test and measurement device is fabricated to have finger-like projections overlaying a portion of the LCD screen for creating the appearance of the continuation of displayed LCD softkey separation lines.

Abstract: A new oscilloscope design improves the processing of acquired voltage-versus-time data through the efficient high speed acquisition and rasterization of such data into a form that includes multiple-bits-per-pixel intensity information. The multi-bit-per-pixel variable intensity rasterizer is optimized for maximum throughput and most efficient use of memory bandwidth. In the presence of faltering trigger rates, rasterization interruption provides a high probability of capturing the data associated with the slow triggers. Circuitry is provided to compensate for acquisition time and amplitude non-linearities. Many-bits-per-pixel intensity information is mapped into a fewer-bits-per-pixel format by a controllable transfer function that provides multiple viewing capabilities for the operator. Another mode of operation emphasizes infrequent events over commonly occurring ones using variations in brightness or color.

Abstract: A system for producing a signal representing an envelope waveform corresponding to the minimum and maximum excursions of an underlying signal includes a source of the underlying signal and a signal acquisition circuit coupled to the underlying signal source. A circuit for calculating the envelope of the underlying signal is coupled to the signal acquisition circuit to produce an envelope signal. A rasterizer, coupled to the signal acquisition circuit and to the envelope calculating circuit, generates the envelope waveform representative signal being a single raster displaying waveforms representing the envelope signal and the underlying signal.

Abstract: A new oscilloscope design improves the processing of acquired voltage-versus-time data through the efficient high speed acquisition and rasterization of such data into a form that includes multiple-bits-per-pixel intensity information. The multi-bit-per-pixel variable intensity rasterizer is optimized for maximum throughput and most efficient use of memory bandwidth. In the presence of faltering trigger rates, rasterization interruption provides a high probability of capturing the data associated with the slow triggers. Circuitry is provided to compensate for acquisition time and amplitude non-linearities. Many-bits-per-pixel intensity information is mapped into a fewer-bits-per-pixel format by a controllable transfer function that provides multiple viewing capabilities for the operator. Another mode of operation emphasizes infrequent events over commonly occurring ones using variations in brightness or color.

Abstract: Unusual waveforms are defined in terms of how many “new” pixels are affected by the process of rasterizing them. New pixels can be those not yet affected by the rasterization of any waveform in the current set of acquisitions, or to be those that have had higher values in their raster memory location but have now been decayed to below a defined value. Once detected, such waveforms can be re-rasterized with extra intensity or into a different color by using a reserved range of values of those storable in the raster memory. Alternatively, the special region of values can be used as a counter/timer to maintain the pixels associated with unusual waveforms at a brightest intensity value, or in the color equivalent, for an extended period of time. User input can be used to affect the definition of “new” pixels and to control the special persistence given to unusual waveforms. Unusual waveforms can also be saved in long term memory.

Abstract: An electronic instrument with a housing defining a module chamber. An electronic module is removably retained within the chamber and includes indicia such as text or a distinctive color on a selected surface of the module. The housing has a window aperture into the chamber, so that the module indicia are visible through the window to permit identification of the presence and identity of the module, even when the instrument is powered off. The module contains electronic circuitry that connects to electronic contacts of the instrument in the chamber.

Abstract: The invention relates to a transit modulator for jittering a signal (Uin) comprising a memory (3), a clock generator (2) connected to said memory (3) and generating a jitter free input clock (T) as well as a further clock generator (5) connected to said memory (3) and generating a jittered output clock (Tj). It is the object of the invention to provide a transit modulator which allows any kind of signals and thus also non-binary digital signals to be jittered. This object is accomplished according to the invention by a transit modulator in which an A/D converter (1) is pre-connected and a D/A converter (4) is post-connected to said memory (3).

Abstract: An electronic instrument with a housing having a front surface and a rear surface. A user interface is located on the front surface. A movable handle having a grip portion is connected to the housing and is movable between a first carrying position in which at least a portion of the grip is forward of the rear surface and a first stabilizing position in which at least a portion of the grip is rearward of the rear surface. The handle may movable to other stabilizing positions, and the housing may include a front prop to provide additional stability and alternative viewing angles.

Abstract: A delta-sigma modulator includes an integrator which includes an integrating amplifier having an input terminal and an output terminal. A pole of a first single-pole-double-throw (SPDT) switch is coupled to a first electrode of an input capacitor, while a first throw of the first SPDT switch is coupled to an input signal source, and a second throw is coupled to a source of reference potential (ground). A pole of a second SPDT switch is coupled to a second electrode of the capacitor, while a first throw of the second SPDT switch is coupled to the input terminal of the integrating amplifier. A feedback signal generator has an input terminal coupled to the output terminal of the integrating amplifier, and an output terminal directly coupled to a second throw of the second SPDT switch.

Abstract: A measuring device for the interface of a transmission link with full-duplex transmission in two-wire common band operation includes a device for simulating the interface that allows the signal in the near-to-far direction on the transmission link to be separated from the return signal. To precisely perform jitter measurements on the interface of the transmission link during ongoing transmission using a conventional jitter measuring instrument, the measuring device has a differentiator followed by a comparator connected between a subtractor and the jitter measuring instrument.

Abstract: A method for determining the period of a periodic signal, possibly including noise, includes the step of calculating a signal representing the difference between the periodic signal, and the periodic signal delayed by a time T. The variance of the difference representative signal is then computed. The steps of computing a difference signal, and determining the variance of the difference signal is repeated for different times T. The period of the periodic signal is determined to be the time T producing the minimum variance. Apparatus implementing this method includes a source of the periodic signal. A difference circuit computes a signal representing the difference between the periodic signal, and the periodic signal delayed by a time T, and a variance circuit computes a signal representing the variance of the difference representative signal. A control circuit varies the time T. A minimum selector selects the time T producing the minimum variance as the period of the periodic signal.