"Multisim仿真设计实现调制解调功能的电路"

The document "Modulation and Demodulation Circuit Design Based on Multisim" discusses the use of phase-locked loop frequency detection for modulation and demodulation in communication circuit systems. This method is favored for its stability, low distortion, and high signal-to-noise ratio. The project focuses on designing modulation and demodulation circuits for 2ASK, 2PSK, and 2FSK signals. These circuits take digital baseband signals, modulate them to produce analog signals, and then demodulate them using a phase-locked loop to recover the digital signals. Multisim software is employed for simulation analysis of these circuits. The waveform distortion in the output of the low-pass filter for the 2ASK, 2PSK, and 2FSK demodulation circuits is significant. However, after passing through the sample decision circuit for reshaping, the digital baseband pulses can be regenerated. The overall hardware circuit design aims for simplicity and practicality while meeting the functional requirements. In conclusion, the project successfully demonstrates the design and simulation of modulation and demodulation circuits using Multisim software, with a focus on phase-locked loop frequency detection. The implementation of these circuits showcases their effectiveness in maintaining signal integrity and achieving high performance in communication systems.