Hello, welcome to Analog Arts oscilloscope tutorial.

Please feel free to download the Demo application software from analogarts.com to help you follow this seminar.

For this presentation, we use a 2 channel 1GHz bandwidth oscilloscope, one of the instruments of SL987.

In this instrument, all the user controls unique to CH1 are grouped in the CH1 panel.

Similarly, all the controls unique to CH2 are grouped in the CH2 panel.

Besides these two panels, there are a display mode panel, a timing panel, a trigger panel, a data acquisition mode panel, a bandwidth panel and a utility panel.

Each individual button in these panels allows the user to perform a unique task. Together, they control the various features of the oscilloscope.

In order to illustrate these features, we first provide a real life application. We connect CH1 to a 5V, 50 KHz sine-wave with a 10X scope probe and connect CH2 to a 4V, 500 KHz square-wave using a coax cable.

We also connect the external trigger input of the oscilloscope to the CH1 corresponding triggering signal.

The oscilloscope originally resets to its default settings. Depending on the application, these settings might not be suitable.

In order to have accurate measurements, we must first choose the proper probe setting. Since we are using a 10X scope probe for CH1, 10X, the default setting, is appropriate.

The green buttons in CH1 panel adjust the vertical scale of the oscilloscope.

The button marked with the up arrow increases the voltage range, whereas the button marked with the down arrow decreases it.

With the 10X probe setting, the vertical scale can be changed from 20 Volts per division to 20m Volts per division.

If the signal amplitude is outside the vertical range of the screen, clipping occurs.

When this happens, the data is no longer valid. The data information panel highlights this condition in red.

Once, the voltage setting is adjusted for CH1 such that clipping does not occur, the maximum voltage of the signal, its minimum, its peak-to-peak value, and its frequency are accurately displayed in their corresponding panels.

The button with a left pointing arrow in the timing panel reduces time per division and the button with the right pointing arrow increases it.

The range of the timing scale adjustment is from 1nS per division to 100mS per division.

In order to view a full cycle of the signal on CH1, we need to adjust the timing scale to 2us/div.

Notice that, the data corresponding to the position of the mouse is also displayed near its position in each channel's corresponding color.

Turning on the AC button in the CH1 panel, switches the input coupling from DC to AC.

Adding a 1 Volt offset to the signal has no effect on the CH1 plot when the oscilloscope input is AC- coupled. However, switching back to the DC mode shows that the signal level is indeed raised by 1 volt.

Removing the 1 Volt offset brings the signal to the middle of the screen again.

Turning on the button labeled "GND", disconnects CH1 from the signal and connects it to the GND level. This is usually done to find and observe the GND reference on the screen.

The yellow arrow on the right side of the screen indicates the 0 or the GND level.

The positions of arrows, signals, and markers can be changed both vertically and horizontally. To do this, left click the mouse near the signal or the arrow and while holding the mouse down move it to the intended position and then release the mouse.

Be aware that each time the channel vertical scale is changed its corresponding horizontal arrow resets back to the middle of the screen.

Now, let's turn on CH2. Since, the frequency of the signal on CH2 is different from the signal frequency on CH1, in order to properly view the signal we need to change the trigger setting from CH1 to CH2, adjust the timing scale, and also the voltage scale. For this signal with frequency of 500 KHz, 500ns/division is an appropriate timing scale.

Since we are using a coax cable for CH2, the 1X scope probe setting must be used.

Although the signal on CH 1 is not triggered, signal information is accurately displayed in the panel.

The blue arrow on the right side of the screen indicates the 0 or the GND level for CH2. Moving the arrow changes this level.

The signal on each channel can be inverted by the "Invert" buttons.

They can also be added and subtracted by the "CH1+CH2" button in the CH1 panel and the "CH1-CH2" button in the CH2 panel.

The trigger panel allows the user to trigger on CH1, CH2, and or on an external signal.

The orange arrow on the left side of the screen shows the trigger threshold level, which is set at 0, its default value. The trigger threshold level can be changed by moving this arrow.

When the vertical setting of the channel on which the oscilloscope is triggered on, is changed the trigger threshold is reset back to 0, its default value.

The horizontal orange arrow on the bottom of the screen indicates the position of the trigger point. The position of this arrow can also be changed. This arrow resets to its default position each time the timing scale is changed.

We can also use the external triggering of the scope, which is presently connected to the triggering signal corresponding to the CH1 input.

Clicking, the button marked "Falling" in the trigger panel, changes the trigger polarity from the rising edge to the falling edge of the trigger signal.

We have been using auto triggering until now. In this mode, regardless of whether the triggering condition occurs or not, the screen is refreshed.

Changing the trigger level to a condition that will never happen illustrates this operation.

In the auto triggering mode, if we move the triggering level outside the signal range, although we lose the triggering condition, the screen is still refreshed asynchronously.

In the normal mode, however, the screen is updated only when the triggering condition is met. Clicking the normal button changes the triggering to this mode.

Since the triggering level is outside the range of the signal, the screen holds the previous data and is no longer updated.

Changing the trigger threshold to a level inside the signal range makes the screen refresh synchronously again.

The single mode trigger, as its name would suggest, updates the screen the first time the triggering condition is met and holds the data forever, regardless of any other conditions.

This is a useful feature to catch a glitch, or a random event. To activate it simply click on the button marked "Single".

As we have expected, the screen updated only once.

Changing back the triggering to the auto mode makes the screen refresh continuously again.

Each channel also provides the user with a set of horizontal markers for analyzing the signals. They are turned on and off by clicking the "Marker" buttons.

The voltage difference between the horizontal markers are updated and displayed at the screen's top right (for CH1) and bottom right (for CH2) in their corresponding colors.

There is also a set of timing markers, which can be used for timing and frequency measurements. They are activated by clicking on the button "Markers" in the timing panel.

The corresponding time and frequency data are displayed at the left bottom corner of the screen.

The timing panel also features the "Zoom In" and the "Zoom Out" buttons.

The zoom-in feature allows the user to select a portion of the signal and zoom on it. To illustrate this, let's change the timing to 20 ms/div., to see a bigger segment of the buffer memory.

Then, we select a portion of the screen by the timing markers and click on the "Zoom-in" button. Notice that the screen displays the selected portion now.

The zoom-in action is undone by clicking the "Zoom Out" button.

The data acquisition panel features "Sampling," "History," "Average," "Envelope," and "Peak-detect" mode.

To have a better understanding of the different types of acquisition modes, the input to CH1 is replaced with a white noise signal having an AC RMS value of 1V.

To view this signal properly, CH1 vertical scale is set at 500 mV per division, and the timing is set at 500 nS per division.

The "Sampling" mode, the mode we have been using up to now, selects some of the data points stored in the buffer memory and presents the data in the form of a plot on the screen at the refresh rate speed.

The information between the selection points is lost.

Also, each time the screen is updated the previous data is erased from the screen.

"Sampling" offers a uniform sampled data suitable for timing measurements. In this mode, the screen displays the white noise as expected.

In the "History" mode however, the screen retains the data.

The number of the retained acquired data can be changed by entering the desired value in the sample textbox.

This number can range from 1 to 256.

To maintain all the previous data simply input an "i" in the sample text box. Notice the older data are displayed with a lesser intensity.

"History" tracks the signal changes and displays a collective set of data. It is the method of choice for observing signal variations over time.

In the "Average" mode, the displayed signal is the average of a number of consecutively acquired data points.

The number entered in the sample text box determines how many sets of data are averaged.

This number can range from 1 to 256. "Average" is best suitable for repetitive signals. This mode removes the uncorrelated noise and the high frequency content of a signal.

Since CH1 input is noise, increasing the number of averages reduces the amplitude of the displayed signal.

An averaging number of 100 has a dramatic effect on the signal.

The "Peak- detect" mode continuously finds the highest and the lowest data values in the acquired data and displays them on the screen.

The number in the sample text box specifies the number of the consecutive data points that are displayed on the screen.

This number can range from 1 to 256. "Peak- detect" is a suitable method for identifying high frequency contents of a signal.

Notice that after a few acquisitions, a band corresponding to the minimum and the maximum values of the signal appears on the screen.

Higher number of the samples specified in the text box makes these bands more defined.

The "Envelope" mode produces a cumulative set of minimum and maximum values at each time point. This is similar to the "Peak-detect" mode performed on multiple acquisitions.

Here, the display retains the previous data for the number of times specified in the sample text box. This number can also range from 1 to 256.

Each mode offers its own unique advantages and is suitable for certain applications.

The small signal 3dB bandwidth of the oscilloscope is 1GHz. In case, the application environment contains high frequency noise and the intended signal to be observed is low frequency, the oscilloscope bandwidth can be adjusted to reduce this unwanted noise.

Square waves demonstrate the effect of bandwidth reduction better than other signals. Therefore, to observe the effect of bandwidth reduction, a 5 V, 2.5MHz square wave is applied to CH1.

Turning on the bandwidth limit button in the bandwidth panel reduces the bandwidth to its default value of 50MHz.

Specifying a different value in the bandwidth text box changes the bandwidth accordingly. This value can range from 20 to 50MHz.

Clicking the bandwidth limit button to the off condition, disables the bandwidth limit and changes the oscilloscope bandwidth back to 1 GHz.

Up to this point we have been using the YT display mode of the oscilloscope, where the vertical axis represents the amplitude of the signal and the horizontal axis represents time.

In the XY mode the X axis no longer represents time.

To illustrate oscilloscope XY mode of operation, let's connect both channels to sine wave sources of about 500 KHz.

Here, the screen plots the variation of CH1 signal with respect to the variation of CH2 signal. The Y-axis represents CH1 signal and the X-axis represents the signal on CH2.

Notice the plot in pink.

This plot, which is known as a Lissajous pattern shows the phase difference between the two signals.

Since the frequencies of the sine waves are identical, this pattern changes from a straight line to a circle.

When the signals are exactly in phase, a -45 degree straight line appears. This line represents a zero degree phase difference between the signals.

When the signals have a 180 degree phase difference, the line's angle becomes a positive 45 degree.

A 90 degree phase difference produces a circle.

If the frequencies are not identical, different patterns appear.

The "XY" mode is a useful feature for vector monitoring and phase analysis.

To turn off the XY mode simply click on it.

The utility panel on the top of the screen allows the user to perform a number of tasks. The " Reset" button brings the oscilloscope to its default condition.

The "Auto Set" button automatically finds the best voltage and timing scales for the present signals.

The "Pause" button freezes the screen and holds the data as long as the oscilloscope is in this mode. Clicking the button again, which is marked "Run" now switches back the oscilloscope to its normal mode of operation.

The oscilloscope settings can be saved in a text file. To do this, simply click on the "Save-Settings" button.

The "Recall Settings" button allows the user to load any desired settings.

In addition to the settings, the user can save the oscilloscope plot and recall it at anytime. The plot can be saved in a variety of formats.

The "Save Ref" button enables the user to save a signal plot as a reference for a later use. To load the reference signal, click on the "Recall Ref" button.

Notice, the reference signal is plotted in white color.

Those applications in which signals are tested against a reference can benefit from this feature.

To remove the reference signal from the screen, click on the "Remove Ref" button.

The "Calibrate" button allows the user to start the self calibration process of the oscilloscope at anytime. This process usually takes about 10 seconds to complete.

The "Display" button hosts a set of features, which enable the user to easily configure the display to his or her likings.

They help the user to personalize the color of each channel, the color of the screen, the order by which the channels are plotted, and customize the screen grid.

Clicking the "Print" button sends the oscilloscope plot to a printer selected by the user.

The "Help" button guides the user to an online Analog Arts information site that hosts a collection of user manuals, specifications, and useful application documentations and videos.

We hope you have enjoyed this presentation.

For additional information please send an email to info@AnalogArts.com.

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