Agilent Technologies, Inc.

Hewlett-packard Company

Keysight Technologies, Inc.

Dennis J Weller

Steven D Draving

Matthew S Holcomb

Robert H Noble

Thomas Schmidt

David W Long

Ralph Urban

An oscilloscope includes at least one demonstration signal generator integrated as part of the oscilloscope. The demonstration signal generator generates stimulus signals that consist of digital samples of various different stored waveforms without the need of a separate demonstration board or signal source. The demonstration signal generator may loop through different sections of the stored waveforms to generate respective stimulus signals that include sequences of digital samples from the different waveforms in combination, to provide a broad range of stimulus signals. The stimulus signals may be displayed on the oscilloscope or output from the oscilloscope as demonstration mode stimulus signals to demonstrate the capabilities of the oscilloscope to customers or for training.

Oscilloscope with internally generated mixed signal oscilloscope demo mode stimulus, and integrated demonstration and training signals

An apparatus, includes an oscilloscope and a waveform generator. The waveform generator is integrated in a common housing with the oscilloscope, and configured to provide a stimulus signal as an output of the apparatus and to provide a trigger signal that is connected internally to the oscilloscope for triggering the oscilloscope.

Oscilloscope with integrated generator and internal trigger

A real time DSO is equipped with a Digital Trigger Filter that performs high frequency rejection, low frequency rejection, AC and DC triggering. The Digital Trigger Filter includes first and second digitally implemented IIR (Infinite Input Response) Filters. A digitized Conditioned Input Signal is applied to the first IIR Filter. It has taps that provide the Trigger Signal outputs needed for high and low frequency rejection. The high frequency rejection output of the first ER Filter is essentially a low pass output (3 dB down at 50 KHz) and is also used as the digital input to the second IIR Filter, whose output is a much more aggressive suppression of high frequencies (3 dB down at 50 Hz). The AC Trigger Signal output is produced by subtracting the output of the second IIR filter from the original input to the entire Digital Trigger Filter, and the DC Trigger Signal output is simply the same as that original input. A MUX selects which Trigger Signal is applied to a Digital Trigger Comparator.

Digital trigger filter for a real time digital oscilloscope

Trigger jitter in an internally triggered real time digital oscilloscope can be reduced through correcting the horizontal position value obtained from a conventional trigger interpolation mechanism by an error or substitute amount learned from an inspection of the acquisition record that notes where in the acquisition record the signal actually crossed the trigger threshold. The display (and measurement) sub-systems that utilize the selection by panning and zooming of a portion of the acquisition record for viewing (and measurement) are supplied with the acquisition record portion of interest, and with an associated horizontal position value that originates with trigger interpolation and that may be subsequently modified by panning. After the trigger circuit detects the trigger condition for a new acquisition record, the voltage threshold for the trigger level in use by the trigger circuit can be compared to the region proximate the trigger location in the acquisition record to determine by further local interpolation the precise location in the acquisition record where the triggering event should have occurred. This allows the determination of a correct and jitter free horizontal position value. Actual display of the desired portion of each new acquisition record then proceeds by supplying to the display rendering system a corrected associated horizontal position value. This reduction in visible trigger jitter is also beneficial to measurements made on the displayed trace.

Trigger jitter reduction for an internally triggered real time digital oscilloscope

A single cable, single point stimulus and response probing system allows the measurement of both low impedance stimulus measurements and high impedance response measurements using a single probe cable. Circuitry located within the probe cable receives stimulus input from the stimulus circuitry located within a test and measurement device, and delivers input to response measurement circuitry also located within the test and measurement device. Certain embodiments of the probing system use feedback supplied to an amplifier located within the stimulus circuitry to improve the accuracy of the measurement device and control output impedance. Feedback can be locally supplied from the output of the stimulus circuitry, or can be generated using an additional amplifier located within the response measurement circuitry.

Single cable, single point, stimulus and response probing system and method

Method and apparatus for automatic verification of measurement probe functionality and compensation for a wide range of oscillating signal amplitude levels. The invention includes a source of an oscillating signal and a measurement device. A measurement probe is coupled between the measurement device and the source of the oscillating signal, wherein it is desired that the probe is functioning to faithfully transmit the oscillating signal there through. The measurement device is adapted for generating a measurement signal in response to the source of the oscillating signal. Also included is a reference that is based upon actual characteristics of the oscillating signal. A controller is coupled with the measurement device and the reference for making a comparison of the measurement signal to the reference. The controller automatically determines whether the measurement probe is functioning based upon the comparison.

Method and apparatus for automatic verification of measurement probe

A gray scale binary field corresponding to each of the pixels on a raster scan oscilloscope display. Each gray scale binary field has a portion of its bits assigned to correspond to the graphical information and a portion of its bits assigned to correspond to the sampled current and prior waveforms. A decrementing state machine, in a predetermined cycle of operation, periodically reads all of the gray scale binary fields in the display memory of the oscilloscope, decrements each value by a predetermined amount such as the binary value of one, and re-writes the decremented binary values back into the display memory. As these decremented gray scale binary fields are displayed, the older waveforms become uniformly more faded with the oldest waveform having the dimmest illumination. In a typical mode of operation, the predetermined cycle of operation corresponds to the sampling of each new waveform from the system under test so that each subsequent prior waveform is decremented by the predetermined amount. In order to minimize flicker, the first prior waveform is still illuminated at full brightness, along with the current waveform. However, the second prior waveform and all older prior waveforms linearly fade in illumination.

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Colorado Springs, CO, United States of America

Dennis J Weller