Oscilloscopes are operated using the front-panel controls, which are divided into four main groups — the horizontal and vertical controls, input controls and the triggering controls.
Found in the front-panel section marked Horizontal, the horizontal controls of the oscilloscope allow users to adjust the display’s horizontal scale. This section includes the control for the horizontal delay (offset) as well as the control that indicates the time per division on the x-axis. The first control allows users to scan through a range of time, while the latter enables users to zoom in on a particular range of time by decreasing the time per division.
Meanwhile, the oscilloscope’s vertical controls are generally located in a section specifically marked Vertical. The controls found in this section allow users to adjust the display’s vertical aspect, and include the control that indicates the number of volts per division on the display grid’s y-axis. Also found in this section is the control for the waveform’s vertical offset, which translates the waveform up or down the display.
Triggering on the signal helps provide a usable and stable display and enables users to synchronize the oscilloscope’s acquisition on the waveform of interest. The trigger controls of the oscilloscope allow users to choose the vertical trigger level as well as the desired triggering capability. Common triggering types include glitch triggering, edge triggering and pulse-width triggering.
Useful for identifying random errors or glitches, glitch triggering enables users to trigger on a pulse or event whose width is less than or greater than some specified length of time. This triggering mode allows users to capture errors or glitches that do not occur very often, making them very hard to see.
The most famous triggering mode, edge triggering occurs when the voltage exceeds some set threshold value. This mode allows users to choose between triggering on a falling or rising edge.
Although pulse-width triggering is comparable to glitch triggering when users are looking for pulse width, it is, however, more general since it allows users to trigger on pulses of specified width. Users can also select the polarity of the pulses to be triggered and set the trigger’s horizontal position. This enables users to view what occurred during pre-trigger or post-trigger.
The input controls of an oscilloscope commonly comprise two or four analog channels. They are usually numbered and features a button associated with every channel that allows users to turn them on and off. This section may also include a selection that enables users to specify DC or AC coupling. Choosing the DC coupling implies that the entire signal will be input. The AC coupling, on the other hand, blocks the DC component and focuses the waveform around zero volts. Users can also specify the probe impedance of the channels through a selection button. In addition, the input controls allow users to select the type of sampling to be used.
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