Abstract: A self-adjusting hold-off trigger circuit and method detects a threshold crossing between consecutive samples of a digitized input signal as edge events, identifies the crossing as a qualified trigger event if the crossing is in a desired direction based upon trigger criteria, and provides a trigger output when the qualified trigger event occurs greater than an approximate average or peak time after a preceding edge event.

Abstract: A waveform compression and display technique saves both a peak detected version (background version) and a decimated/lowpass filtered version (foreground version) of a sampled electrical signal. The two versions are displayed simultaneously overlaid together in a contrasting manner so as not to obscure information contained in either of them. The lowpass filtered version uses a series of simple lowpass filters with decimation to produce a single data stream from a plurality of data streams derived from the sampled electrical signal. The single data stream may then be subjected to additional filtering, such as a cascaded integrator-comb filter, to obtain a desired frequency bandwidth. When displayed, the peak detect pixels adjacent the decimated/lowpass filtered pixels may be adjusted in intensity so that the low frequency information of the lowpass filtered waveform is not lost, while the peak detect pixels further from the lowpass filtered pixels are intensified to highlight the high frequency information.

Abstract: An accessory device voltage management system includes an accessory device selectively coupled to a host. The host provides a bulk power supply and a low power supply voltage to the accessory device. The host receives accessory device parameters from the device and determines if the accessory device is a valid and supported device and, if so, sends commands to the accessory device to couple the bulk power supply voltage to a power supply circuit in the accessory device. The power supply circuit in the accessory device generates at least a first regulated voltage output.

Abstract: A test and measurement Instrument samples an input digital logic signal to produce logic samples, compresses the logic samples into compression codes, and stores the compression codes into acquisition memory. Compression includes parsing the logic samples into groups and assigning compression codes to those groups, and is performed so as not to lose information about the input digital logic signal's activity. The instrument converts the stored compression codes into a waveform image in display memory and displays the stored waveform image on a display device.

Abstract: A test and measurement instrument includes a memory configured to store a digitized signal, a display configured to display the digitized signal, a mark interface configured to generate a mark creation signal, a processor coupled to the memory, the display, and the mark interface. The processor is configured to identify a feature of the digitized signal and create a mark indicating the feature and the digitized signal in response to the mark creation signal.

Abstract: A simple, integrated control for pan and zoom of a display of data represented by a very long data record is in the form of a control knob having an outer ring for controlling pan and an inner knob for controlling a zoom factor. A zoom function is turned ON either by turning the inner knob (setting the zoom factor to a default value) or by (i) pressing an adjacent zoom or pan button or (ii) turning the outer ring (setting the zoom factor to a prior value when the zoom function was turned OFF). The zoom function may be turned OFF by turning the inner knob to set the zoom factor to 1× or by pressing the zoom button. The outer ring has individual positions divided into two groups: one group for controlling pan rate within a zoom window displaying a portion of the very long data record defined by a zoom box within a main window displaying the very long data record; and the other group for controlling pan rate of the zoom box within the main window for rapid movement from one end of the record to another.

Abstract: A method of characterizing a newly acquired waveform with respect to previously acquired waveforms during monitoring of a generally repetitive signal, where the previously acquired waveforms have been rasterized into a two-dimensional array of memory locations, reads history values for those memory locations associated with an active portion of the newly acquired waveform, compares the history values with history value ranges, increments a count for one of a plurality of recent pixel counters corresponding to the history value ranges, each counter having a different history value range, and modifies the history values in the memory locations. From the counts accumulated for each of the history value ranges the variability of the newly acquired waveform from the generally repetitive signal is determined.

Abstract: A multi-instrument triggering system includes in each instrument trigger system a system ready line for coupling an internal ready signal to an external port. A multi-instrument trigger bus cable connects the external ports, trigger event outputs and trigger event inputs of multiple instruments together in such a way as to enable the trigger generators in the instruments when all instruments are ready to receive a trigger event. When enabled, a coordinated trigger is generated in response to an internal trigger event from at one of the instruments. The coordinated trigger is coupled via the multi-instrument trigger bus cable as the trigger event to trigger all instruments in synchronism.

Abstract: A test and measurement instrument includes a trigger system for controlling an acquisition system to acquire digital signal samples. The trigger system is selectively responsive to a trigger circuit for detecting a trigger event associated with an input signal, and to circuitry for detecting various sequences or combinations of anomalies. Further, selected sequences and combinations of the anomalies may be combined across a plurality of channels of the test and measurement instrument, or across multiple instruments, thereby allowing more sophisticated triggering criteria to be defined.