Experiment 2 - Introduction to the Oscilloscope

Tasks:

In this laboratory, the handling of the oscilloscope and a function generator will be learned.

If you have questions regarding the setup of the oscilloscope or the function generator, refer to the handbook and the internal help-button first.

1.0 Make sure the oscilloscope settings are correct to be able to save images to USB and insert a USB-Flashdrive. Once an image should be saved, simply push the save button next to the display.

1.1 Start with displaying the signal that the not connected probe is picking up. What do you see? Try to move the line across the screen.

1.2 Now the function generator should be used to display some different signals. Start the internal function generator (button gen) and connect channel 1 of the fg-output to the input via BNC-cable. Now select sine-wave with 5kHz and 250mV(peak-to-peak). Now switch on the internal function generator output.

a) Use the auto-set button on the oscilloscope to display the sine-wave. If the oscilloscope shows a sine-wave you can start setting it to 100us/div and 500mV/div.

b) Now change the frequency of the sine-wave to 10kHz in the internal function generator settings. What do you see on the oscilloscope now? Try to display the same amount of periods as in 1.2a. Save to USB.

1.3 a) Find out about the frequency and the peak-to-peak amplitude of the sine-wave on the oscilloscope by using the measure button. Save to USB.

b) Next, use the full screen to display the signal, then use the cursors to find out how long one period of the sine-wave is. Save to USB.

c) Use the cursors to measure the amplitude of the signal. Compare your answer to 1.3a.

1.4 Now exactly one Period should be displayed on the oscilloscope. Try to display the signal starting with a phase of 0° on the left side on the display without changing the horizontal position. How do you need to set the trigger? Save to USB.

2.1 Now we need the additional external function generator. Keep channel 1 connected to the internal function generator (5kHz, 250mV). Connect the external function generator output to channel 2 of the oscilloscope. Set the external function generator to a sine-wave with 4kHz and 250mV amplitude (peak-to-peak). Set the oscilloscope to xy-mode (app selection – xy). What kind of Lissajous figure do you see?

a) Try to change the signal of the external function generator to display a circle on the oscilloscope. What did you have to change? Save to USB.

b) Change the frequency of the external function generators signal to double the frequency of the internal function generator. Try to display a figure that looks like the number 8 or the infinity-sign. What had to be changed here? Save to USB.

3.1 Disconnect Channel 2 and select output off for channel 2 on the external function generator. Now go into the generator-menu of the oscilloscope again and set the output to a sine-wave with 5kHz and 1V_pp. Scroll down a little and for modulation select AM and 500kHz. Switch on the output.

a) Try to use the trigger to get a stable view of the signal on the oscilloscope. Save to USB.

b) Measure the frequency of the envelope. Save to USB.

4.1 Switch off the internal function generator output. Only connect a passive probe to channel 1 of the oscilloscope.Go into the pattern-generator menu and select square-wave with 1Hz, switch on the pattern state. Connect the ground clip to the ground of the pattern-generator-output and the probe tip to P0 by using the hook. What signal do you see?

Now disconnect the probe from P0 and remove the hook from the tip.

a) We now want to display the start of the signal once the tip of the probe is touching P0. To do this, use single mode and set your trigger level. Once single mode is active, connect the probe tip to P0. This might need a few tries to catch the correct moment, experiment with different scales until you can see the moment when the probe is being connected. Save to USB.

After all steps are done, sort all images into one folder, name it according to the group and name all images according to their tasks (e.g. "1.2b.bmp").

Sources:

[1]     Rohde & Schwarz GmbH & Co. KG, „R&S RTB2000 Digital Oscilloscope: User Manual“, München.

[2]     Tektronix Inc., „AFG3000 and AFG3000C Series Arbitrary Function Generators: User Manual“.

[3]   I. Hickman, Digital storage oscilloscopes. Oxford: Newnes, 1997.