Digital Oscillator Phase Synchronization for Low-Jitter RF Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing high-frequency signal generation technologies, particularly in radio-frequency power supplies, face challenges such as slow frequency response, high jitter, and cost inefficiency due to the reliance on analog components and expensive fast analog-to-digital converters, limiting their accuracy and reconfigurability in applications like plasma processing and medical equipment.
Innovation Solution
A device and method utilizing a phase control circuit and digital oscillator circuit to synchronize periodic high-frequency power signals with external reference signals, incorporating an analog-to-digital converter and loop filter to reduce jitter and enable faster frequency conversion, while using a frequency tuning word for efficient phase locking and up/down-conversion, thereby improving digital phase locked loop performance and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If phase-locked loop (PLL) is used to lock the frequency of voltage controlled oscillator (VCO) to a certain harmonic or combination frequency, then the desired frequency output can be generated, but the response to frequency changes is slow
Solution Approach 1:
The patent replaces the traditional analog PLL mechanism with a direct digital frequency synthesis approach. The frequency synthesizer uses a phase accumulator and lookup table to generate frequencies directly in the digital domain, eliminating the need for analog VCO and PLL components. This substitution enables instantaneous frequency changes while maintaining accurate frequency generation through digital control words, thereby resolving the contradiction between fast response speed and frequency locking accuracy.
2Measurement precision
If very fast analog-to-digital converters are used for high-frequency signal generation, then measurement accuracy is maximized, but the cost increases significantly
Solution Approach 1:
The patent uses direct digital frequency synthesis to create accurate frequency copies through mathematical calculations rather than physical signal conversion. The phase accumulator generates phase values that are converted to amplitude values using a lookup table, effectively copying the desired signal characteristics in the digital domain. This approach achieves high measurement accuracy without requiring expensive fast analog-to-digital converters, as the frequency generation itself is performed digitally with precise control.
3Adaptability or versatility
If external reference is directly connected to the frequency synthesizer input with frequency dividing, then the reference frequency can be adapted, but frequency up-conversion is limited by the DDS-system's internal multiplication
Solution Approach 1:
The patent extends the frequency range capability by adding an external reference input that can be multiplied by a programmable factor N. This creates a new dimension for frequency adaptation beyond the internal DDS multiplication limits. The system can now accept external reference frequencies and upscale them through the phase accumulator's frequency multiplication capability, achieving frequency up-conversion ratios up to 2^32 times the reference frequency, thereby resolving the limitation of internal DDS multiplication.
Data Source
AI summary
A device for synchronizing a periodic high frequency power signal (18) and an external reference signal (10). The device comprises a phase control circuit (100) and a digital oscillator circuit (130). The digital oscillator circuit (130) is connected to the phase control circuit (100). The digital oscillator circuit (130) comprises means for generating the periodic high frequency power signal (18) dependent on the control signal from the phase control circuit. The phase control circuit (100) is configured to determine a phase difference of the periodic high frequency power signal (18) and the external reference signal (10).