Abstract: A test and measurement instrument including a plurality of digitizers, each digitizer configured to digitize an input signal to generate a digitized signal; a signal processor configured to combine at least two of the digitized signals from the digitizers into a combined signal; and a circuit configured to receive the combined signal.

Abstract: Embodiments of the invention include an apparatus and method for displaying trigger frequency on a display of a test and measurement instrument. During each of a series of equal time intervals, a number of trigger events are counted. Each trigger event count is associated with a corresponding logical column of a trigger display window. The trigger event counts are written to memory locations associated with the corresponding logical columns of the trigger display window. Trigger frequency logic generates multiple trigger frequency indicators based on the trigger event counts. The trigger frequency indicators are displayed in the trigger display window to quickly and efficiently convey trigger density information to a user of the test and measurement instrument. The apparatus includes jitter reduction logic to reduce or eliminate unwanted jitter related to the trigger frequency indicators.

Abstract: A test and measurement instrument according to an embodiment of the present invention converts digital data that represents an analog input signal into a time-domain bitmap, and then compares a region of that time-domain bitmap to a density threshold. When the density value violates the density threshold, a trigger signal is generated that causes digital data to be stored into a memory.

Abstract: A test and measurement instrument and method for providing post-acquisition trigger control and presentation of associated waveforms on a display. An electrical signal under test is sampled and digitized, and stored in an acquisition memory as a data record. A display device draws a waveform associated with the signal under test. After the acquisition of the digital samples is stopped, a user selects trigger criteria using trigger controls such as a trigger level control. A trigger circuit detects a post-acquisition trigger event in the data record based on the trigger criteria causing an automatic adjustment of the waveform to conform to a time of the post-acquisition trigger event. One or more configurable trigger controls can be used to adjust a display of post-acquisition trigger events and waveforms. Upon resumption of the live-acquisition of data, the live waveform conforms to the newly selected trigger criteria as previewed during the post-acquisition mode.

Abstract: A waveform display apparatus and method displays one or more waveforms of a signal under test at high throughput while acquiring digital data of the signal under test in a large acquisition memory. A user sets a time interval of user's interest when viewing a signal under test and sets trigger criteria through a user interface. An ADC converts the signal under test into digital data that is stored in a large acquisition memory. A trigger unit detects and produces trigger events, based on a trigger, as trigger event information during one acquisition process. A trigger event eliminator may discard some of the trigger events based on pre-trigger and post-conditions set through the interface by a user. The trigger events are recorded in a trigger list as the trigger event information. A control unit locates the digital data in the acquisition memory corresponding to the trigger events in the trigger list and displays a waveform associated with the trigger event for the time interval on a display device.

Abstract: An improved hold-off algorithm that assures that all data associated with all trigger events in a data signal are displayed uses a designated interval starting with a first trigger event to determine whether any subsequent trigger events occurred within the designated interval. A first display frame is drawn based upon the first trigger event. A next display frame is drawn based either on a next trigger event that occurs outside the designated interval, or based on the last trigger event that occurred within the designated interval. In the latter case the two display frames provide an overlap to assure that no data related to the trigger events is lost on the display.

Abstract: A digital storage oscilloscope employs an improved edge triggering circuit that discards some of trigger events when it determines that there are many more trigger events than the oscilloscope can use. The determination is made in response to detection of a characteristic of the signal that indicates a repetitive nature of a complex signal. Certain trigger events are selected to be acted upon, and others are discarded, in response to the determination. The circuitry dynamically reacts to changes in the input signal in response to detection of different criteria for a characteristic of repetition as the input signal changes.

Abstract: Pre-trigger and post-trigger acquisition for a no dead time acquisition system, where the data being displayed does not include a related trigger event, has a variable record length buffer having a maximum record length equal to a maximum desired pre-trigger interval, and has a trigger FIFO and timer for delaying the related trigger event. The record length of the buffer is determined by the desired pre-trigger interval, and fast rasterizers access the oldest data that encompasses the desired pre-trigger data. A first trigger event in the trigger signal may be delayed by a desired post-trigger interval before the fast rasterizers begin drawing the waveform data that encompasses the desired post-trigger data.

Abstract: A test and measurement instrument and method for providing post-acquisition trigger control and presentation of associated waveforms on a display. An electrical signal under test is sampled and digitized, and stored in an acquisition memory as a data record. A display device draws a waveform associated with the signal under test. After the acquisition of the digital samples is stopped, a user selects trigger criteria using trigger controls such as a trigger level control. A trigger circuit detects a post-acquisition trigger event in the data record based on the trigger criteria causing an automatic adjustment of the waveform to conform to a time of the post-acquisition trigger event. One or more configurable trigger controls can be used to adjust a display of post-acquisition trigger events and waveforms. Upon resumption of the live-acquisition of data, the live waveform conforms to the newly selected trigger criteria as previewed during the post-acquisition mode.

Abstract: A waveform display apparatus and method displays one or more waveforms of a signal under test at high throughput while acquiring digital data of the signal under test in a large acquisition memory. A user sets a time interval of user's interest when viewing a signal under test and sets trigger criteria through a user interface. An ADC converts the signal under test into digital data that is stored in a large acquisition memory. A trigger unit detects and produces trigger events, based on a trigger, as trigger event information during one acquisition process. A trigger event eliminator may discard some of the trigger events based on pre-trigger and post-conditions set through the interface by a user. The trigger events are recorded in a trigger list as the trigger event information. A control unit locates the digital data in the acquisition memory corresponding to the trigger events in the trigger list and displays a waveform associated with the trigger event for the time interval on a display device.

Abstract: A test and measurement instrument including a plurality of digitizers, each digitizer configured to digitize an input signal to generate a digitized signal; a signal processor configured to combine at least two of the digitized signals from the digitizers into a combined signal; and a circuit configured to receive the combined signal.

Abstract: A test and measurement instrument and method for providing post-acquisition trigger control and presentation of associated waveforms on a display. An electrical signal under test is sampled and digitized, and stored in an acquisition memory as a data record. A display device draws a waveform associated with the signal under test. After the acquisition of the digital samples is stopped, a user selects trigger criteria using trigger controls such as a trigger level control. A trigger circuit detects a post-acquisition trigger event in the data record based on the trigger criteria causing an automatic adjustment of the waveform to conform to a time of the post-acquisition trigger event. One or more configurable trigger controls can be used to adjust a display of post-acquisition trigger events and waveforms. Upon resumption of the live-acquisition of data, the live waveform conforms to the newly selected trigger criteria as previewed during the post-acquisition mode.

Abstract: A test and measurement instrument and method for providing post-acquisition trigger control and presentation of associated waveforms on a display. An electrical signal under test is sampled and digitized, and stored in an acquisition memory as a data record. A display device draws a waveform associated with the signal under test. After the acquisition of the digital samples is stopped, a user selects trigger criteria using trigger controls such as a trigger level control. A trigger circuit detects a post-acquisition trigger event in the data record based on the trigger criteria causing an automatic adjustment of the waveform to conform to a time of the post-acquisition trigger event. One or more configurable trigger controls can be used to adjust a display of post-acquisition trigger events and waveforms. Upon resumption of the live-acquisition of data, the live waveform conforms to the newly selected trigger criteria as previewed during the post-acquisition mode.

Abstract: An improved hold-off algorithm that assures that all data associated with all trigger events in a data signal are displayed uses a designated interval starting with a first trigger event to determine whether any subsequent trigger events occurred within the designated interval. A first display frame is drawn based upon the first trigger event. A next display frame is drawn based either on a next trigger event that occurs outside the designated interval, or based on the last trigger event that occurred within the designated interval. In the latter case the two display frames provide an overlap to assure that no data related to the trigger events is lost on the display.

Abstract: Pre-trigger and post-trigger acquisition for a no dead time acquisition system, where the data being displayed does not include a related trigger event, has a variable record length buffer having a maximum record length equal to a maximum desired pre-trigger interval, and has a trigger FIFO and timer for delaying the related trigger event. The record length of the buffer is determined by the desired pre-trigger interval, and fast rasterizers access the oldest data that encompasses the desired pre-trigger data. A first trigger event in the trigger signal may be delayed by a desired post-trigger interval before the fast rasterizers begin drawing the waveform data that encompasses the desired post-trigger data.

Abstract: A data management method for a long record length memory that is used for data acquisition writes data samples into an initial circular buffer within the memory having a size equal to a pre-trigger time. When a first trigger event occurs, the data samples are then written into a linear region after the circular buffer within the memory. The data sample acquisition in the linear region continues until a post-trigger and new pre-trigger time have elapsed after a last trigger event, at which point the acquisition terminates and the new pre-trigger time becomes a new circular buffer for a next trigger event. In this way all trigger events are captured with associated pre-trigger and post-trigger data.

Abstract: A data management method for a long record length memory that is used for data acquisition writes data samples into an initial circular buffer within the memory having a size equal to a pre-trigger time. When a first trigger event occurs, the data samples are then written into a linear region after the circular buffer within the memory. The data sample acquisition in the linear region continues until a post-trigger and new pre-trigger time have elapsed after a last trigger event, at which point the acquisition terminates and the new pre-trigger time becomes a new circular buffer for a next trigger event. In this way all trigger events are captured with associated pre-trigger and post-trigger data.