Oscilloscope
An oscilloscope (or “scope”) allows you to view signal voltages, typically in a two-dimensional graph where one or more electrical potential differences (on
the vertical axis) are plotted as a function of time or of some other voltage (on the horizontal axis).
Most of the time, oscilloscopes are used to show events that repeat with either no change or change slowly.

1. Menu
See Menu in Common Interfaces.
1.1. View

2. Toolbar


The trigger controls allow you to stabilize repeating waveforms and capture single-shot waveforms.
- Single button: starts a single acquisition.
- Run/Stop button: starts repeated or continuous acquisition (see Scan Mode). While the acquisition is in progress, the Run button becomes the Stop button.
- Mode: The three trigger modes are:
- Normal: the acquisition is triggered only on the specified condition. The oscilloscope only sweeps if the input signal reaches the set trigger point.
- Auto: when the trigger condition does not appear in 2 seconds, the acquisition is started automatically. In repeated acquisition mode, when the instrument switches to auto trigger, the next acquisitions are made without waiting again to timeout while a trigger event does not occur and the configuration is not changed. When a new trigger event occurs, or the configuration is changed, the current acquisition will be finished and the next one will wait for the trigger again. It is also the best mode to use if you are looking at many signals and do not want to bother setting the trigger each time.
- None: the acquisition is started without a trigger.
- Buffer: The performed acquisitions are stored in the PC buffer in time order. This makes it easy to review a series of repeated acquisitions. The new acquisitions are stored after the currently selected buffer position. If you change the position in the buffer and start a new acquisition, the positions after the selected one will be lost. The number of buffers (Buffer Size) can be specified in the control options.
- Run: The options in Run mode select the action of the Run button and are the following:
- Repeated mode: the Run button starts repeated acquisitions.
- Scan Screen mode: scan acquisition where the sampled data is drawn from left to right. When the right corner is reached, the signal curve plot continues from the left.
- Scan Shift mode: similar to the screen mode, but when the signal plot reaches the right corner, the curve plot slides to the left.
The scan modes (Screen and Shift) are available when the time-base is greater than 100 ms/division. Below this value, the repeated mode is used for the Run button.
- Source: The trigger source selects the oscilloscope channel that is used for the trigger. Other instruments or external trigger signals can be used to trigger the oscilloscope.
- Type: The trigger type selects between edge, pulse, and transition.
- Edge: Edge triggering is the basic and most common type. For edge triggering, the trigger level and slope controls provide the basic trigger point definition. The trigger circuit acts as a comparator. You select the slope and voltage level of one side of the comparator. When the trigger signal matches your settings, the oscilloscope generates a trigger.
The slope-condition control determines whether the trigger point is on the rising or the falling edge of a signal.
A rising edge is a positive slope and a falling edge is a negative slope.
The level control determines where the trigger point occurs on the edge. The following figure shows you how the trigger slope and level settings determine the waveform display.
Triggering on rising edge | Triggering on falling edge |
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Pulse: If the trigger type is set to Pulse, then the oscilloscope will trigger if a positive/negative pulse has a larger/smaller length than the one already set by the user. For example, if the pulse is smaller than the length set, and the triggering condition is set to more, the oscilloscope will not trigger.
The picture below shows a positive pulse trigger configured for less than 200 µs.

The picture below shows a positive pulse trigger configured for time-out at 200 µs.

The picture below shows a positive pulse trigger configured for more than 200 µs.

- Transition: The transition trigger is similar to the pulse trigger, but here the transition time of a signal is compared with the specified length. The low and high transition levels are specified by the hysteresis window.
The picture below shows a rising transitions trigger from -3V to +3V configured for less than 200 µs.

The picture below shows a rising transitions trigger from -3V to +3V configured for time-out at 200 µs.

The picture below shows a rising transitions trigger from -3V to +3V configured for more than 200 µs.

- Filter: The trigger sample selects the sample mode that will be used by the trigger detector. This can be different from the one used for acquisition, which is why the trigger event might not be visible on the acquired data.
- Condition: The trigger condition for edge and transition type selects between rising or falling edge. For pulse trigger it selects between positive or negative pulse.
- Level: The trigger level is the adjustable voltage level at which the scope triggers when the trigger input crosses this value. See
Trigger Hysteresis and Trigger Types.
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Hysteresis: Using hysteresis, low and high levels are determined (the trigger level plus and minus the hysteresis value). When the signal level exceeds the high level, it is considered as high and it stays high until falling below the low level. This is used to avoid bouncing caused by signal noise and also to specify the transition trigger conditions.

The picture below shows how, without hysteresis, the trigger event also occurs on the falling edge of the input signal, due to signal noise.

- Length Condition: The trigger length condition selects between less, time out, or more for pulse length or transition time. See Pulse Trigger and Transition Trigger.
- Trigger Length: The trigger length specifies the minimal or maximal pulse length or transition time. See Pulse Trigger and Transition Trigger.
- Holdoff: The trigger holdoff is an adjustable period of time during which the oscilloscope will not trigger. This feature is useful when you are triggering on complex waveform shapes, so the oscilloscope triggers only on the first eligible trigger point.
The following figure shows how the trigger holdoff helps to create a usable display.

Trigger with 10ms holdoff

Trigger without holdoff
The holdoff length should be around the maximum burst length, preferably a little bit more, but not less than this. For the above situation, the holdoff value should be around 6ms, but lengths between 6 and 15 ms are also acceptable.
3. Channels
This toolbar contains the time and channel configuration groups. The toggle button in the top-left edge enables/disables the auto hiding of this toolbar.

Add Channel button opens a drop-down with the following options:
The check-box before the group name enables or disables the respective channel. The properties drop-down button in the top-right corner allows you to configure the channel properties. The mathematic and reference channels also have a close button.
3.1. Time Group


Use the time group to position and scale the waveform horizontally using the time base and the horizontal trigger position controls.
- Position: The horizontal position control moves the waveform left or right to exactly where you want it on the screen.
It actually represents the horizontal position of the trigger in the waveform recording. Varying the horizontal trigger position allows you to capture what a signal did before a trigger event (so-called
“pre-trigger viewing”).
Digital oscilloscopes can provide pre-trigger viewing because they constantly process the input signal, whether a trigger has been received or not.
Pre-trigger viewing is a valuable troubleshooting aid. For example, if a problem occurs intermittently, you can trigger on the problem, record the events that led up to it, and possibly find the cause.
- Base: The time base (seconds/division) setting from the channel configuration toolbar lets you select the rate at which the waveform is drawn across the screen. This setting is a scale factor.
For example, if the setting is 1 ms, each horizontal division represents 1 ms and the total screen width represents 10 ms (ten divisions). Changing the sec/div setting allows you to visualize longer or shorter time intervals of the input signal.
- Offset as division: selects the unit of the offset parameter, division, or seconds.
- Range Mode: selects the display mode for time base (per division, plus-minus, and full).
- Sample Rate: adjusts the sample rate.
- Samples: adjust the number of samples to acquire.
- Digital Sample Rate: adjusts the sample rate for digital channels.
- Samples: adjust the number of samples to acquire for digital channels.
- Rate: this specifies the time period at which the application will check the oscilloscope device status and read the acquired data, in repeat run mode. Increase the time to reduce the update rate.
3.2. Real Channels


Use the real channel (vertical controls) to position and scale the waveforms vertically using the offset and range controls for each channel.
- Offset: The offset (vertical position) control lets you move the waveform up or down to exactly where you want it on the screen. The offset is the voltage difference between the centerline of the oscilloscope screen and the actual ground. This difference is generated by an internal offset voltage source.
- Range: The range (volts/division) controls determine the vertical scale of the graph drawn on the oscilloscope screen.
The volts/div setting is a scale factor. For example, if the volts/div setting is 2 volts, then each of the ten vertical divisions represents 2 volts and the entire screen can show 20 volts from bottom to top. If the setting is 0.5 volts/div, the screen can display 5 volts from bottom to top, and so on. The maximum voltage you can display on the screen is the volts/div setting multiplied by the number of vertical divisions.
In the property drop-down, the following can be configured:
- Color: sets the channel waveform color.
- Offset as division: selects the unit of the offset parameter, division or voltage.
- Noise: shows or hides the noise band (min/max values).
- Range mode: selects the display mode for the range of the channels (per division, plus-minus, and full).
- Attenuation: specifies the used probe attenuation.
- Sample Mode: sets the acquisition sample mode. The oscilloscope AD converter works at a fixed frequency. Depending on the time base setting and the size of the oscilloscope buffer, the sampling frequency can be less than the AD conversion frequency. For instance, if the AD conversion frequency is 100 MHz (10 ns), the buffer size is 8000 samples and the time base is 200 µs/division, then between two samples there will be 25 AD conversions.
The following filters can be applied to the extra conversions:
- Decimate: will record only the Nth AD conversion.
- Average: each sample will be calculated as the average of the AD conversions.
- Min/Max: each two samples will be calculated as the minimum and maximum value of the conversion results.
- Name: specifies the channel name.
- Label: specifies the channel label.
Input Coupling
Coupling is the method used to connect an electrical signal from one circuit to another. In this case, the input coupling is the connection from your test circuit to the oscilloscope.
On the Electronics Explorer board, the input coupling AC and DC are separate input connectors on the board with AC
and DC marks.
On the Analog Discovery BNC Adapter jumper select
between AC and DC coupling.
DC coupling shows all of an input signal. AC coupling blocks the DC component of a signal so that you see the waveform centered at zero volts.
The following diagram illustrates this difference. The AC coupling setting is handy when the entire signal (alternating plus continuous components) is too large for the volts/div setting.
DC coupling
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AC coupling
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2V peak-to-peak sine wave with 2V DC component
3.3. Mathematic Channels

The integrated mathematic functions allow you to perform a variety of mathematical calculations on the input signals of the oscilloscope. Simple and Custom mathematic channels can be added with the “Add Channel” button from the Channels. The simple mathematic channel can be configured to add, subtract, multiply, or divide two channels. The mathematic operations are performed by the PC, so the oscilloscope device cannot trigger on these channels. The units for the math channel can be specified, for instance: A, W.
In the property drop-down, the following can be configured:
- Units: lets you specify the channel units.
- Custom: check for custom mathematic function.

Custom Mathematic Channel
The custom or simple mathematic channel can be selected under the channel properties, as shown below.

The Custom Math Function editor can be launched with the bottommost button showing the formula.

You can type the custom function in the Enter Function text box. If the entered function is valid, the resulting number for one sample is displayed, otherwise the error description is listed.
Click Apply to apply changes.
Click OK to save the last valid function.
Click Cancel to use the function saved before the editor was opened.
Accepted values are:
- supported real, added reference, and mathematic channels with smaller index, like: C1, C2, R1, M1.
- Time: time variable expressed in seconds.
- mathematic operations: addition “+”, subtraction “-”, multiplication “*”, division “/”, reminder “%”.
- brackets: parenthesis (), square brackets [].
- functions: Math.log (logarithm), Math.pow (power), Math.min (minimum), Math.max (maximum), Math.sqrt (square root), Math.sine, Math.cos, Math.tan, Math.acos, Math.atan, Math.atan2, Math.abs (absolute value), Math.round, Math.floor, Math.ceil.
- constants: Math.E, Math.PI, Math.LN2, Math.LN10.
3.4. Reference Channels
The reference channels can be added using the “Add Channel” button from the Channel toolbar.

In the property drop-down, the following can be configured:
- Units: lets you specify the channel units.
- Lock time: when checked, the time configuration of the reference channel follows the main configuration. When unchecked custom time setting is used for this channel.
- Position: lets you adjust the position of the reference waveform.
- Base: lets you adjust the scale factor of the reference waveform.
- Update: updates reference channel with the selected channel waveform or imported data from file.
4. Main Plot

- The center of the display is marked with grid lines. Each vertical and horizontal line constitutes a major division. These are laid out in a 10-by-10 division pattern. The tick marks on the sides between major divisions are called minor divisions. The labeling on the oscilloscope controls (volts/div and sec/div) always refer to major divisions.
- On the left side of the view, the horizontal voltage grid line marks are shown for the active channel. Left-mouse dragging changes the offset and right-dragging adjusts the range of the active channel.
- The time marks of the vertical grid lines are located at the bottom. Left-mouse dragging changes the time (trigger horizontal) position and right-dragging adjusts the time base.
- On the right side of the view, left-mouse dragging changes the vertical trigger level and right-dragging adjusts the hysteresis level.
- The channel list colors make channel identification easy. Left-mouse click a rectangle activates the channel. Right-mouse click disables/hides it.
- The status label shows the state of the oscilloscope. See Acquisition States for more information.
- The horizontal trigger position arrow can be dragged with the mouse.
- The zero point arrows for each channel can be dragged with the mouse to change the vertical position (offset).
- The vertical trigger position arrow can be dragged with the mouse to change the trigger level. The two smaller arrows represent the low and high levels
(hysteresis).
- The drop-down button (in the top-right corner or mouse right-click) contains options for:
- Color: selects the color theme for this plot.
- Plot Width: sets the thickness of the waveform, expressed as points.
4.1. HotTrack
The HotTrack lets you take measurements by moving the mouse cursor. When the mouse cursor position is close to a waveform slope, it will place a vertical cursor and two more towards left, measuring the pulse width and period. Otherwise, it will place one vertical cursor showing the time position and the waveform's level at the intersections with the vertical cursor.

4.2. XY Cursors
The X and Y cursors are available for main time view and zoom time plots. These can be moved with mouse horizontal or vertical drag. Dragging with left mouse button moves the cursor and with right button the pair of cursors (X1 and X2 or Y1 and Y2) is moved keeping the distance between them.
The X or vertical cursors by default are in the bottom-left and the Y cursors in top-right corner.
4.3. Digital Channels
The Logic Analyzer can be enabled inside the Oscilloscope interface by adding digital channels, or by enabling from the view menu.
The picture below shows the analog output of a binary counter on a Pmod-R2R.
5. Views
5.1. XY
Using the XY view allows you to plot one channel against another. This plot could be the I-V curve of a component such as a capacitor, inductor, or diode, or a Lissajous figure showing the phase difference between two periodic waveforms. XY view is also capable of more advanced operations, such as plotting a math channel against a reference waveform.
The properties button in the top-left corner opens a drop-down to select the channels for X and Y representation.

5.2. Histogram
A histogram is a graphical representation of the voltage distribution in a signal waveform. It plots the distribution of values for each voltage value, with the number of times the signal has a certain voltage value represented as a percentage.
The picture below shows the histogram view of a sine and another signal.
The properties button in the top-left corner or mouse right-click opens a drop-down to select scaling.

5.3. Data
The Data view displays the acquisition samples and the time stamps.

The first column shows the sample index, the second shows the time stamp followed by the values for channels.
The selected cells can be copied and pasted to other applications.
5.4. Measurements
The Measurements view shows the list of the selected measurements. The first column in the list shows the channel, the second shows the type, and the third shows the measurement result. At the top are Add and Remove buttons and up and down buttons to change the order of the measurements in the list.
Pressing the Add button opens the Add Measurements window. On the left side is the channel list, and on the right side is a tree view containing the measurement types in groups. Below it is the current value of the measurement and a short description. Pressing the Add button here (or double-clicking an item) adds it to the measurement list.


Vertical-axis measurements for each channel:
- Maximum: the absolute largest value.
- Minimum: the absolute smallest value.
- Average: the mean value between maximum and minimum values.
- Peak2Peak: the difference between the extreme maximum and minimum values.
- High: pulse top settled value according to the histogram.
- Low: pulse bottom settled value according to the histogram.
- Middle: the middle value of the pulse between top (High) and bottom (Low) settled values.
- Overshoot: = (Peak to Peak / 2 - Amplitude) /
Amplitude.
- Rise Overshoot: = (Maximum - High) / Amplitude.
- Fall Overshoot: = (Minimum - Low) / Amplitude.
- Amplitude: half of the difference between the pulse top (High) and bottom (Low) settled value.
- DC RMS: Direct Current Root Mean Square is the entire power contained within the signal, including AC and DC components.
- AC RMS: Alternating Current Root Mean Square is used to characterize AC signals by subtracting out the DC power, leaving only the AC power component.
5.5. Logging
See Logging in Common Interfaces.
6. Export
See Export in Common Interfaces.