Hewlett-packard Company

Agilent Technologies, Inc.

Keysight Technologies, Inc.

Matthew S Holcomb

Michael L Beyers

Daniel P Timm

Warren S Tustin

Allen Montijo

Kenneth D Poulton

Dennis J Weller

Robert M R Neff

Michael R Fender

Kristopher A Larsen

Thomas Schmidt

Robert A Witte

Joseph D Shaker

Steven J Pelelo

Connor P McKay

Brian W Kerr

Marshall Boss

James Kang

A system and method are provided for displaying input signals from a DUT on a display screen. The method includes sending a data stream of digitized data received from the DUT to an FPGA for serial decoding; receiving decoded symbols from the FPGA; identifying valid symbols among the decoded symbols indicating transitions between the decoded symbols; storing the valid symbols with corresponding time-tags as valid packets in memory, and discarding ones of the decoded symbols occurring between the valid symbols; and plotting on the display screen the valid packets occurring between beginning and ending valid packets of the stored valid packets. The beginning valid packet has a corresponding time-tag occurring immediately before a first point time-tag associated with a left edge of the display screen, and the ending valid packet has a corresponding time-tag occurring at or immediately before a last point time-tag associated with a right edge of the display screen.

System and method for performing lossless compressed serial decoding

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

A system and method: receive an input signal and output digital samples representing the input signal; store the digital samples for at least one acquisition record of the input signal in an acquisition memory; detect a trigger event in the input signal and calculate a trigger address in the acquisition memory for a digital sample corresponding to the detected trigger event; perform digital signal processing on the digital samples of the acquisition memory to produce processed digital samples; detect an edge, representing a trigger, in the processed digital samples, and determine a measured trigger time; temporarily store the processed digital samples in a buffer memory at least until the edge detector detects the edge in the processed digital samples; determine a trigger correction value in response to the measured trigger time; determine a corrected beginning address of the buffer memory from the calculated trigger address and the trigger correction value; and read the processed digital data out from the buffer memory beginning at the corrected beginning address.

One-pass trigger jitter reduction for digital instruments

A digital oscilloscope comprises a sampling unit configured to sample an input signal received from an oscilloscope probe to produce a first stream of digital samples, a first acquisition system configured to store and process the stream of digital samples to produce a first data set, a second acquisition system configured to store and process the first stream of digital samples independent of the first acquisition system to produce a second data set, and a display system configured to concurrently display the first data set in a first format and the second data set in a second format different from the first format.

Digital oscilloscope comprising multiple data acquisition pathways

A method of generating a trend graph comprises storing a stream of data elements in a buffer having a storage capacity corresponding to a first number of data elements, compressing the stored data elements to fit within a display having a size corresponding to a second number of data elements smaller than the first number of data elements, detecting an event, and as a consequence detecting the event, compressing the stored data elements to occupy a reduced portion of the buffer.

Dynamic creation of trend graph

A device includes a memory storing a persistence bit for each of a plurality of pixels of a display device, the persistence bit having a first value when a corresponding pixel should be illuminated for displaying a persistent image, and having a second value when the corresponding pixel should not be illuminated for the persistent image; a pseudorandom pixel value generator which during each video frame receives a seed value and generates pseudorandom pixel values for the plurality of pixels, each pseudorandom pixel value being not greater than a specified variable persistence value; a frame value generator outputting a frame value for each video frame; and a match detector which, during each video frame, compares the frame value to the pseudorandom pixel values for the plurality of pixels, and for each pixel where the comparison indicates a match, makes the persistence bit for the corresponding pixel have the second value.

Device for displaying a waveform with variable persistence and method of providing the same

A method of calibrating a high-speed analog to digital converter and an ADC that implements the method. Multiple linear regression analysis is used to calibrate the stages of a pipeline ADC to compensate for variations in gain from stage to stage and optionally to compensate for harmonic distortion. Current amplifiers each having gain of about 1.6 are used for low power consumption, minimal surface area requirements, and rapid sampling speed. Weighting factors are stored in lookup tables to minimize the number of adders required to generate the output digital word.

Method of calibrating an analog-to-digital converter and a circuit implementing the same

A method of connecting displayed samples of a signal, where the samples are obtained by sequential or random repetitive sampling. Three example embodiments are presented. In a first embodiment, the system decides whether or not to connect to the next consecutive sample, based on the outcome of comparison of the magnitude of the slope to a slew rate threshold. In the second embodiment, the system looks ahead (or behind) up to M samples to see if any samples represent valid slew rates, and connects to the first sample representing a valid slew rate. In the third embodiment, the system looks ahead (or behind) M samples and connects to the sample in the next M samples that represents the smallest valid slew rate. In each embodiment, if no sample represents a valid slew rate, no connection is drawn. In the second and third example embodiments, by looking ahead (or behind) M samples, the system can potentially resolve a waveform with up to M phases and can accommodate trigger placement uncertainty.

Reconstruction of multi-phase signals from repetitive samples

A self-framing serial trigger within an oscilloscope or specialized analyzer construes an absence of the data's clock signal for at least a selected length of time as implying the occurrence of a framing signal. This frees the serial trigger from otherwise needing an externally supplied framing signal. The serial trigger may include a shift register containing the most recent N-bits of the data, which is then bit-wise compared to the trigger pattern (stored in a register). This level of comparison may provide for don't care bits in the trigger pattern. The results of this bit-wise comparison are then inspected for a certain uniformity indicating that the trigger pattern has been matched. An additional circuit may count clock signals since the last implied framing pulse. If this additional count has not yet reached M (or counted down from M to zero) the match is premature, and no trigger signal is generated. The implied framing signal itself may be generated by loading a down counter with a preselected value each time a selected edge occurs in the clock for the data. The down counter is clocked by a high speed clock running several times faster than the clock for the data. If the down counter ever reaches zero a framing pulse is implied. The implied framing pulse may be generated by decoding a value of zero in the down counter.

Self-framing serial trigger for an oscilloscope or the like

Each acquisition record in a random repetitive oscilloscope is time stamped and stored in a location in the acquisition memory indexed by the associated value of trigger offset. Those acquisition records that are older than a selected and variable amount can be discarded instead of being used to contribute data to the waveform record. This has the effect of preventing old data from intruding into a new measurement. When reformulating the waveform record to pan or zoom while using data already acquired, it is possible to ensure that the newest waveform records are included in that reformulation. This has the effect of ensuring that new data is displayed. The time stamp may be a binary count of an elapsed time interval, in units of the sample clock, since some cardinal event, such as the last time ERASE or RESET was pressed. To maximize the random distribution of the trigger offsets represented in the acquisition memory, the rule for deciding which of m-many acquisition records receives this latest data is based on the trigger offset. The first of the acquisition records gets acquisitions whose trigger offsets are at least zero but less than 1/m of a sample period t, the second receives acquisitions whose trigger offsets are at least t/m but less than 2 t/m, and so on.

Digital oscilloscope with pan and zoom produced from time stamped data

A method, and circuit for implementing the method, allow a deep memory digital oscilloscope or logic analyzer to rapidly display large data records. Incoming signals are 'dually' processed through multiple data compression circuits so as to create and store at least two data records. A smaller record is available for immediate and rapid display. A larger record is available for subsequent panning & zooming. By storing sequential data records in alternating memory divisions and eliminating data moves, the larger record may also be viewed more rapidly.

Method of rapidly displaying large data records retrieved by deep memory

In a test instrument, display locking is reduced by the addition of a non-constant time delay to each acquisition cycle. The time delay may be randomly chosen or follow a predetermined algorithm. Decreased system throughput caused by the addition of a non-constant time delay may be minimized by alternately storing acquired data in two acquisition memories. Display locking may also be reduced by rejecting selected triggers. The data acquired from these selected triggers is not processed for display. The triggers whose data is not processed for display may be randomly chosen or they may be chosen by a predetermined algorithm. Rejecting triggers and the addition of a non-constant time delay may be used in combination or individually to reduce display locking.

Method for reducing display locking in digital oscilloscopes or logic

A new sampling technique for waveform measuring instruments (including methods and circuits for implementing same) comprises the step of processing a series of digital signal samples through a decimator to extract a decimated sample value from each decimated sample interval in a series of decimated sample intervals. The series of digital signal samples is simultaneously processed through a digital peak detector to extract maximum and minimum values (peak detect sample values) from each decimated sample interval. For a given decimated sample interval, a difference between the maximum and minimum sample values for the interval is calculated. If the difference exceeds a glitch detect threshold value, the maximum and minimum sample values for the given decimated sample interval are transferred to a video sample memory. If not, the decimated sample value for the given decimated sample interval is transferred to the video sample memory.

Sampling technique for waveform measuring instruments

An oscilloscope has a trigger circuit which is operable in any one of three different modes. The trigger circuit has a number of edge detect circuits which generate pulses in response to a rising edge, falling edge, or both rising and falling edges of one or more signals. The trigger circuit has a multiplexer which routes one of three signal sources depending upon the selected mode. With a first mode, the multiplexer routes signals from a pattern detect circuit and the trigger circuit operates in a conventional manner to trigger based on the duration of the signal. In the second mode, the multiplexer routes signals from one edge detect circuit and the trigger circuit measures the frequency or rate of the signal. In the third mode, the multiplexer routes signals from a flip-flop which generates a pulse based upon the outputs from two different edge detect circuits and can be configured to measure setup or hold violations between two signals. The trigger circuit according to the invention can therefore trigger on events more complex than just the duration of a signal and provides this triggering ability without the need for any instrument or circuitry external to the oscilloscope.

Time duration trigger

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].

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Colorado Springs, CO, United States of America

Matthew S Holcomb