Oscilloscope Features Overview

Oscilloscope

• Measures voltage changes over a specific time interval
• Displays signal changes as a repeating waveform

Oscilloscope Features

• X-axis
  • Displays time per division (sec/div)
  • Waveform period = (sec/div) * number of divisions
  • Frequency = 1 / period
• Y-axis
  • Displays voltage per division (V/div)
  • Voltage = (V/div) * number of divisions
  • Vp: Peak voltage, Vpp : Peak-to-peak voltage
• Waveform Display
  • 𝐹(𝑡) = 𝐴 ⋅ sin 𝜔𝑡 + 𝜃 = 𝐴 ⋅ sin(2𝜋𝑓𝑡 + 𝜃)
    • A: Amplitude (V), f: Frequency (Hz), 𝜃: Phase (rad)
• Other Features

  • High input impedance, providing more accurate readings than a multimeter

  • Requires practice to use effectively

  • Different models have similar functionalities

  • RMS (Root Mean Square) value of a sinusoidal waveform:

                                           𝑡0 +𝑇            𝑉𝑝
                                   1           2
                       𝑉𝑟𝑚𝑠 =      ⋅න       𝑉 (𝑡) 𝑑𝑡 =
                                   𝑇 𝑡0                   2
    

Function Generator

• Generates various types of waveforms and outputs them as voltage
• Outputs: Sine wave, Square wave, Triangle wave
• Adjusts output amplitude with an amplitude control

Lab 6-1: Oscilloscope & Function Generator

• Objective:*
• To understand the usage of the oscilloscope and function generator.
• Procedure:*

1. Preparation and Basic Experiments:
   • Understand terms related to the oscilloscope: Focus, Intensity, Horizontal and Vertical Position, AC-GND-DC Switch, Signal Input, Mode Switch, Trigger Control.
   • Connect the function generator to the oscilloscope input channel and set the function generator to output a 1kHz sine wave
   • Set the oscilloscope vertical sensitivity to 1 V/div and the function generator voltage to 2V to achieve a 4Vpp sine wave.
2. Waveform Measurement:
   • Set the oscilloscope to display a 5kHz, 6Vpp sine wave and a 100kHz, 4Vpp square wave.
   • Record the waveform shape and the settings used (ms/div, V/div).
3. RMS Value and Error Measurement:

   • Calculate the RMS value of a 1kHz, 4Vpp sine wave and record it.

   • Measure the RMS value of the function generator's output using a digital multimeter and record it.

   • Calculate the % error:

                                    𝑉𝐴 −𝑉𝑀
                       %오차 =             × 100%
                                  𝑉𝐴 
     

   • Where 𝑉𝐴 = calculated value, 𝑉𝑀 = measured value

4. Results Validation
   • Present the filled-in results table and diagrams.
   • Answer any questions from the instructor.

Digital and Analog Data Processing

Digital Data

• Input: pinMode(pinNo, INPUT); digitalRead(pinNo);
• Output: pinMode(pinNo, OUTPUT); digitalWrite(pinNo, value);

Analog Data

• Input: pinMode(pinNo, INPUT); analogRead(pinNo);
• Output: pinMode(pinNo, OUTPUT); analogWrite(pinNo, dutyCycle);

Periodic Processing Functions

• delay() function:
  • Pauses the program for a specified amount of time.
  • Most microcontroller operations are halted during the delay.
• millis() function:
  • Returns the time elapsed since the program started.
  • Allows other tasks to run while waiting for a specific time interval.

Lab 6-2: Periodic Processing

• Objective:*
• To understand how to create periodic processes using the Arduino platform.
• Procedure:*

1. Button and LED Connection
   • Connect a button and LEDs to the Arduino board.
2. Blink with millis() Function (Sketch 8-3):
   • Use the millis() function to control the blink interval of an LED, allowing other tasks to run simultaneously.
   • Continuously check the elapsed time and update the LED state accordingly.
3. Periodic LED Control - Using delay Function (Sketch 8-1):
   • Use the delay() function to control the blink of LEDs, but this approach will block other tasks from running during the delay.
4. Periodic LED Control - Using millis Function (Sketch 8-4):
   • Combine the millis() function with button input to control the blink of two LEDs.
   • The first LED blinks periodically, while the second LED toggles its state when the button is pressed.
5. Variable Resistance-based Period Control (Sketch 8-6):
   • Use a potentiometer to control the blink interval of an LED.
   • The analogRead() function reads the potentiometer value, and the map() function converts it to a desired interval range.

Lab 6-2 Reference: map() Function

• long map(long value, long fromLow, long fromHigh, long toLow, long toHigh):
  • Remaps a value from one range to another.
  • value: The number to map.
  • fromLow: Lower bound of the input range.
  • fromHigh: Upper bound of the input range.
  • toLow: Lower bound of the output range.
  • toHigh: Upper bound of the output range.

Lab 6-2: Results Check

• Show the Sketch 8-3, 8-5, and 8-6 editing windows.
• Show the execution of Sketch 8-3, 8-5, and 8-6.
• Answer any questions from the instructor.

This quiz covers the essential features and functions of oscilloscopes, including how they measure voltage and display waveforms. Understand the significance of the X-axis and Y-axis for time and voltage, along with waveform equations. Dive into the various functionalities that make oscilloscopes essential tools for accurate signal measurements.