Dual-Oscillator Mixing for Low-Phase-Noise Frequency Generation
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Solution Overview
Problem
Existing oscillator arrangements face challenges in achieving low phase noise, particularly at higher frequencies, due to the difficulty in maintaining phase noise performance and frequency tunability, especially when frequency multiplication is required.
Innovation Solution
The use of two oscillators, an in-loop oscillator and an additional oscillator, where the output frequency is a combination of both, allowing for phase-locked loop control and compensation of frequency deviations, thereby eliminating the need for frequency multiplication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If frequency multiplication is used to achieve higher output frequency, then the output frequency is increased, but the phase noise increases by approximately 6 dB per doubling of frequency
Solution Approach 1:
The patent divides the frequency generation task into two segments: an in-loop oscillator operating at a lower frequency and an additional oscillator operating at a higher frequency. The output frequency is generated by combining these two oscillators through mixing, rather than multiplying a single low-frequency oscillator. This segmentation avoids the phase noise penalty of frequency multiplication while achieving the desired high output frequency.
Solution Approach 2:
The patent transitions from a single-oscillator frequency multiplication approach to a two-oscillator mixing approach, adding a dimensional change in the frequency generation methodology. By using two independent oscillators with frequencies f1 and f2 to generate output frequencies through mixing (producing f1±f2, 2f1±f2, 2f2±f1), the system achieves high output frequencies without the phase noise degradation associated with sequential frequency doubling.
2Object-generated harmful factors
If the Q value of the VCO is increased to reduce phase noise, then the phase noise is reduced, but the frequency tuning range and agility are reduced
Solution Approach 1:
The patent segments the frequency generation function between two oscillators: the in-loop oscillator (VCO) can be optimized for frequency agility and tuning range, while the additional oscillator provides the high-frequency component. This segmentation allows each oscillator to be optimized for its specific role, with the VCO maintaining low Q for fast tuning while the system achieves low phase noise through the combination of both oscillators.
Solution Approach 2:
The patent introduces an intermediary mixing stage that combines the outputs of two oscillators. This intermediary process allows the system to achieve high output frequencies with low phase noise without requiring either oscillator to operate at the full output frequency, thereby maintaining frequency tuning agility while reducing phase noise.
3Speed
If a single oscillator is used to generate high frequency directly, then the frequency is achieved, but the phase noise performance degrades due to the 20 log factor relationship
Solution Approach 1:
The patent segments the high-frequency generation task into two lower-frequency oscillation sources that are combined through mixing. Instead of using a single oscillator that must operate at the full high frequency (suffering from phase noise degradation), the system uses two oscillators at lower frequencies f1 and f2, combining them to produce the high output frequency f1±f2, 2f1±f2, or 2f2±f1, thereby avoiding the phase noise penalty.
Solution Approach 2:
The patent changes the dimensional approach from single-oscillator frequency multiplication to dual-oscillator mixing, fundamentally altering how high frequencies are generated. This dimensional change in the frequency generation architecture allows the system to achieve high output frequencies without the phase noise degradation that occurs when a single oscillator is pushed to high frequencies or when frequency multiplication is applied.
Data Source
AI summary
The present disclosure relates to oscillator arrangement comprising an output port adapted to output an output signal with an output frequency (fout), an in loop oscillator that is adapted for an in loop oscillator frequency (fosc) and an additional oscillator that is adapted for an additional oscillator frequency (foscA). The output frequency (fout): exceeds the in loop oscillator frequency (fosc) and the additional oscillator frequency (foscA), is dependent on both the in loop oscillator frequency (fosc) and the additional oscillator frequency (foscA), and is adapted to control the in loop oscillator frequency (fosc) via a feed-back loop.