Capturing Your Signal
What is an oscilloscope anyway?
An oscilloscope is a diagnostic instrument that plots the amplitude of an electrical signal as it changes over time. The picture below shows the block diagram of an oscilloscope.
- No Signal:
- Is the channel / device under test turned on?
- Is the waveform off the screen? Try the Autoset feature of adjusting the vertical position / scale.
- Is the instrument waiting for trigger? (Is it displaying “Ready”?) Verify trigger source; try adjusting the trigger level, forcing a trigger or switching to auto mode.
- Aliasing: If the frequency of the signal on the screen seems too low, or it is difficult to get a stable waveform on the screen, adjust horizontal scale to increase the sample rate.
- Unexpected measurement results: Verify that probe is compensated, verify measurement settings such as ref levels and gating, verify the probe attenuation.
- No stable signal: Verify trigger source, trigger level.
|Connect the instrument to circuit
|Connect the probe to the input channel of the instrument.
|Check probe compensation: Attach the probe tip to the probe compensation test point on the instrument. Adjust the probe compensation until you see a clean square wave on the screen.
|Connect probe ground to the circuit ground and probe tip to the signal you want to view / measure.
|Set the total amplitude to be displayed on the screen
|Adjusts the size of the waveform on the screen per channel, a larger waveform gives better measurement resolution.
|Moves the waveform up and down on the screen.
|Sets the maximum voltage that can be displayed; scope attenuation setting needs to match probe attenuation.
|Use DC coupling to see all the input signal. Use AC coupling to see only the AC signal riding on top of a DC offset.
|Set the total time to be displayed on the screen
|Sets the amount of time displayed on the screen for all channels.
|Moves the waveform left or right on the screen.
|Stabilize the waveform on the display
|Select which input signal is compared to the trigger settings.
|Edge trigger is the most commonly used trigger type;trigger on rising, falling or both edges. Other more advanced triggers such as Pulse Width, Runt Timeout, Setup and Hold, Rise/Fall Time, Logic and Pattern trigger types are available for capturing more complex events.
|Determines the voltage level on the input signal at which the trigger occurs.
|Measure voltage and time characteristics of signals
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