PWM - Pulse Width Modulation (Basics, Circuit, Working, & Waveforms) Explained
Introduction to Pulse Width Modulation
Overview of PWM Functionality
- The session introduces the concept of pulse width modulation (PWM) and its significance in digital communication.
- It explains how a PWM circuit operates, utilizing a modulating signal to generate varying pulse widths at the output.
- A comparator is used in the circuit to compare the modulating signal with a generated waveform, determining voltage outputs based on their relationship.
Understanding Voltage Outputs
- If the modulating signal (Hp) exceeds the generated waveform (Ct), a positive voltage is produced; conversely, if Hp is less than Ct, a negative voltage results.
- The relationship between these signals is crucial for generating PWM outputs, which are illustrated through waveforms.
Waveform Analysis
Trajectory Tracing in Waveforms
- The speaker discusses tracing trajectories within waveforms to visualize when Hp is greater or less than Ct.
- Positive output occurs when Hp surpasses Ct during specific intervals; negative output arises when Ct exceeds Hp.
Repetition of Output Patterns
- This pattern of alternating positive and negative outputs continues throughout the waveform, creating a pulse width-modulated effect.
- The characteristics of PWM are highlighted: wider positive pulses indicate stronger modulating signals while narrower ones suggest weaker signals.
Advanced Concepts in PWM
Reference Adjustments in Output
- In certain scenarios, if Hp falls below Ct, instead of producing negative voltage, an output of zero can be achieved by modifying circuit components.
Clamping Circuit Integration
- Introducing a clamper circuit allows for adjustments that ensure outputs remain relative to zero voltage rather than dipping into negatives.
- This modification leads to clearer representation of actual voltage signals based on input conditions and enhances understanding of PWM generation.
Conclusion and Future Topics
Transitioning to Pulse Position Modulation