#Training Camp# Simple Oscilloscope

This simplified oscilloscope
from LCSC mimics and replicates an official oscilloscope case study, providing invaluable insights into circuit design.
 
I. Front-end Processing Circuit: The
simplified oscilloscope incorporates an analog front-end processing circuit to achieve AC/DC coupling, input signal attenuation, signal conditioning, and signal frequency measurement.
1) AC/DC Coupling: A sliding switch connects the input signal to different circuit branches. For AC signals, the DC component is filtered out using the capacitor's DC-blocking and AC-passing properties. No processing is applied to DC signals.
2) Input Signal Attenuation: A sliding switch switches between different voltage divider circuits, attenuating the signal amplitude. When the input signal amplitude is small, a lower voltage range should be selected first. If the input signal amplitude is uncertain, a higher voltage range can be used initially. If the amplitude falls within the lower voltage range, the lower voltage range can be used for more accurate measurement results, while simultaneously protecting the circuit. In actual circuit design:


When switches 2 and 3 of SW2 are connected together, the measurable input signal amplitude is -1.6V to 5V.
When switches 2 and 1 of SW2 are connected together, the measurable input signal amplitude is -80V to 250V.

3) Signal conditioning. Design a voltage follower and proportional amplifier to process the signal for easy analysis.
4) Signal frequency measurement. Use a comparator to measure the signal frequency.

II. Human-computer interaction
. The LCSC GD32Ex series minimum system core board is used as the digital processing core. It processes the front-end signals and realizes rich human-computer interaction.
1) A 1.8-inch TFT SPI color display screen is used to display rich information.
2) An EC11 rotary encoder is used for easy operation and smooth operation.
3) LEDs indicate the working status.
4) PWM output terminal outputs a square wave signal with variable frequency and variable duty cycle.