Oscilloscopes: Analog vs Digital Analysis

Oscilloscopes - Analog or Digital

• An oscilloscope is an electronic test instrument that displays electrical signals on a graph.
• The graph, often called a "waveform", shows how signal voltage varies over time.
• Oscilloscopes are used to analyze waveform properties like amplitude, frequency, rise times, time intervals, and distortion.

Voltage Signals on 2D Graphs

• Many electronic signals are periodic, meaning they repeat consistently, like sound waves, heartbeats, and generator outputs.
• These signals can be converted to voltage and displayed over time on a 2D graph, typically with 10 columns and 8 rows of intervals.

2D Graph Properties

• 2D graphs allow observation of voltage signals over time (represented by a V/t graph).
• The Y-axis represents vertical direction, showing signal amplitude (strength).
• The X-axis represents horizontal direction, showing signal time (or frequency).

Reading Properties of a Signal

• By observing the waveform on the oscilloscope, you can measure properties such as:
  • Peak-to-Peak Amplitude: The difference between the maximum positive and maximum negative voltage values.
  • Period: The time it takes for the waveform to complete one cycle.

Oscilloscope Control Layout

• Oscilloscopes have a variety of controls, including:
  • Run/Stop: Starts or stops the waveform acquisition
  • Trigger: Determines the starting point of the waveform display
  • Horizontal Gain: Controls the time scale (t/div) on the X-axis
  • Horizontal Shift: Moves the waveform left or right on the X-axis
  • Vertical Gain: Controls the voltage scale (V/div) on the Y-axis
  • Vertical Shift: Moves the waveform up or down on the Y-axis
  • Cursors: Used for precise measurement of voltage and time intervals
  • Measure: Provides numerical measurements of various waveform properties (like amplitude, frequency, etc.)

Vertical Gain

• Vertical gain scales the waveform vertically, stretching or compressing it along the Y-axis.
• Rotating the vertical gain knob adjusts the V/div display.
• Pressing the knob toggles between Coarse and Fine adjustments, allowing for precise control.

Vertical Shift

• Vertical shift moves the waveform up or down along the Y-axis.
• Rotating the vertical shift knob adjusts the signal's position.
• Pressing the knob aligns the signal with the "zero" position.

### Horizontal Gain

• Horizontal gain scales the waveform horizontally, stretching or compressing it along the X-axis.
• Rotating the horizontal gain knob adjusts the t/div display.
• Pressing the knob toggles between Coarse and Fine adjustments, allowing for precise control.

Horizontal Shift

• Horizontal shift moves the waveform left or right along the X-axis.
• Rotating the horizontal shift knob adjusts the signal's position.
• Pressing the knob aligns the signal with the "zero" position.

Trigger

• The trigger determines the starting point of the waveform display.
• Rotating the trigger knob adjusts the voltage level at which the waveform starts.
• Pressing the knob aligns the signal with the "zero" position.
• You can choose different trigger types like rising-edge or falling-edge to capture specific points in a waveform.

### Oscilloscope - Setting Up a Signal

• To observe a signal on the oscilloscope:
  1. Turn on the power. Allow time for the oscilloscope to boot up.
  2. Apply the signal: Connect the signal to the Oscilloscope's input, choosing Channel 1 or 2.
  3. Find the signal trace: Click "Default Setup" on the oscilloscope. Rotate knobs for trigger, horizontal gain, and vertical gain to reset them to zero. Alternatively, enable "Auto Scale" for automated adjustment.
  4. Set the Voltage divisions: Rotate vertical gain to maximize the viewing of the signal amplitude. Use 5-8 intervals on the Y-axis for optimal viewing. For example, if the waveform has a 4Vp-p amplitude, set Vertical Gain to 2V/div.
  5. Set the Timebase divisions: Rotate horizontal gain to display 1 or 2 full cycles of the signal. Use 5-8 intervals on the X-axis for optimal viewing. For example, if the signal has a 200ms period, set the horizontal gain to 20ms/div or 50ms/div.
  6. Adjust the trigger: Choose a suitable trigger type and voltage level. For example, to capture an event happening once a minute, trigger at 1V rising-edge.
  7. Fine-tune the image: Use the Fine adjustments on vertical and horizontal gains to zoom in for more detail. Remember, this increases the difficulty in measuring amplitude and period.

This quiz explores the functionalities and properties of oscilloscopes, including the differences between analog and digital types. It covers fundamental concepts like voltage signals representation on 2D graphs, waveform properties, and interpretation techniques. Test your knowledge on how oscilloscopes are used to analyze electrical signals over time.