Composite Phase PWM Modulator for Stable High-Speed Signal Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Self-oscillating PWM designs face challenges with non-fixed modulation/sampling frequency, leading to harmonic distortion and non-linearity due to dependence on continuous input signal frequency and amplitude, which affects signal integrity during transmission.
Innovation Solution
A composite phase modulator with a feed-forward loop determining high-level discontinuous signal timing and a feedback loop determining low-level discontinuous signal timing, ensuring a stable PWM modulation/sampling frequency independent of the continuous signal's frequency content and amplitude, along with galvanic isolation and signal conditioning to minimize distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If self-oscillating PWM design is used, then the circuit is simple and adaptive, but the modulation frequency becomes variable and dependent on input signal, causing harmonic distortion and non-linearity
Solution Approach 1:
The patent employs a phase-locked loop (PLL) feedback mechanism where the PWM output frequency is fed back to control the oscillator, ensuring the PWM frequency remains locked to a stable reference frequency regardless of input signal variations. This feedback control eliminates the frequency drift and non-linearity inherent in self-oscillating designs while maintaining circuit simplicity.
Solution Approach 2:
The invention changes the control parameter from input-signal-dependent oscillation (self-oscillating) to reference-frequency-dependent oscillation (PLL-locked). By using a voltage-controlled oscillator (VCO) whose frequency is regulated by the PLL to match a stable reference, the system achieves fixed PWM frequency operation that prevents harmonic distortion while keeping the circuit architecture relatively simple.
2Manufacturing precision
If PWM frequency is made stable and fixed, then signal integrity is improved, but the modulation system becomes more complex requiring precise frequency matching
Solution Approach 1:
The PLL feedback mechanism automatically adjusts the VCO frequency to match the reference frequency, eliminating the need for manual frequency matching and reducing sensitivity to component tolerances. This self-correcting feedback system maintains precise frequency stability without requiring complex external frequency control circuitry.
Solution Approach 2:
The PLL circuit performs self-adjustment by continuously comparing the PWM frequency with the reference frequency and automatically correcting any deviations. This self-regulating mechanism eliminates the need for external frequency stabilization equipment or complex calibration procedures, achieving frequency precision through the system's own internal feedback loop.
3Stability of the object's composition
If feed-forward and feedback loops are implemented, then PWM frequency stability is achieved, but the circuit complexity increases
Solution Approach 1:
The patent combines the feed-forward path (input signal to VCO) and feedback path (PWM output to phase detector) into an integrated PLL circuit. By merging these functions into a single cohesive control loop with shared components like the VCO and phase detector, the system achieves frequency stability without the complexity of separate, independent control circuits.
Solution Approach 2:
The VCO serves multiple functions: it generates the PWM signal, acts as the oscillator for frequency comparison in the PLL, and provides the controlled output frequency. This multi-functionality reduces the need for separate dedicated circuits for each function, achieving frequency stability with minimal additional components beyond the core PLL architecture.
Data Source
AI summary
The present invention relates to a system and a method for pulse width modulation and demodulation of a continuous input signal, which system is configured to receive a continuous input to an analog modulator, which system comprises a demodulator generating a continuous output signal. It is the object of the pending patent application to use an analog modulator for transmitting the signal from the input stage over to an output stage. A further object of the pending patent application is to preserve the signal integrity in regard to precision and to minimize both non-linearities and distortion side effects. The object can be fulfilled by the analog modulator being formed as a composite phase modulator which composite phase modulator comprises at least one feedback loop which feedback loop determines the width of a low-level discrete signal, which composite phase modulator comprises at least one feed-forward loop, which feed-forward loop determines the width of a high-level discrete signal as a function of the continuous input. Hereby it can be achieved that timing between discrete low-level and high-level forms a discontinuous output signal representing the continuous input.