Multiphase Signal Generator Using Open-Loop Phase Interpolation
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Solution Overview
Problem
Existing multiphase signal generators face challenges in accurately generating signals with a fixed phase relationship due to limitations in analog tunable delay elements and complicated feedback structures, leading to increased manufacturing costs and circuit complexity.
Innovation Solution
A multiphase signal generator with a feed-forward open-loop architecture that uses phase shifters and phase interpolators to provide identical phase shifts, allowing for accurate setting of phase relationships between output signals without requiring precise delay matching, thereby reducing circuit overhead and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If analog tunable delay elements and complicated feedback structures are employed to generate signals with fixed phase relationship, then the phase accuracy can be tuned, but the circuit complexity and manufacturing costs increase
Solution Approach 1:
The circuit is divided into multiple identical delay stages, each contributing a fixed phase shift. By segmenting the total phase shift into discrete identical stages, the system achieves accurate phase relationships without requiring complex continuous tuning mechanisms, thus reducing overall circuit complexity while maintaining precision.
Solution Approach 2:
The invention changes the approach from continuous analog tuning to discrete parameter selection. By using multiple identical delay stages with fixed delay values, the system achieves phase accuracy through parameter multiplication rather than continuous adjustment, simplifying the control mechanism and reducing circuit complexity.
2Measurement precision
If analog tunable delay elements are used to achieve accurate phase tuning, then the desired phase relationship can be obtained, but the trimming effort during production increases
Solution Approach 1:
The phase tuning function is segmented into multiple identical delay stages, each with fixed characteristics. This eliminates the need for continuous trimming of single analog components, as the desired phase relationship is achieved by selecting and combining discrete identical stages, significantly reducing production trimming effort.
Solution Approach 2:
Multiple copies of the same delay stage are used instead of single tunable components. By copying the identical delay circuit multiple times and combining them, the system achieves accurate phase relationships through replication rather than trimming, simplifying the manufacturing process.
3Measurement precision
If complicated feedback structures are employed to generate multiphase signals, then the phase relationship can be controlled, but the circuit size increases
Solution Approach 1:
The feedback structure is replaced by segmented parallel delay paths, each generating a specific phase-shifted version of the input signal. This segmentation eliminates the need for complex feedback loops while maintaining precise phase relationship control, thereby reducing circuit size.
Solution Approach 2:
Instead of using feedback to control phase relationships, the invention inverts the approach by using feedforward parallel paths with predetermined delay characteristics. This inversion eliminates the feedback mechanism entirely, reducing circuit complexity and size while maintaining phase control accuracy.
Data Source
AI summary
A multiphase signal generator includes an input port. Furthermore, the multiphase signal generator includes a plurality of phase shifters. Each phase shifter of the plurality of phase shifters is configured to provide an identical phase shift Δφ. At least one phase shifter is connected to the input port. Furthermore, the multiphase signal generator includes a first phase interpolator and at least a second phase interpolator. Each phase interpolator has a respective output terminal. Each phase interpolator is configured to weight a phase of a signal at a respective first input terminal of the phase interpolator with a respective first weighting factor wi,1 and to weight a phase of another signal at a respective second input terminal of the phase interpolator with a respective second weighting factor wi,2 to generate an interpolated phase signal at the respective output terminal of the phase interpolator. A first subset of the plurality of phase shifters includes n>1 serially connected phase shifters. The first subset of phase shifters is coupled between the first input terminal and the second input terminal of the first phase interpolator. A different second subset of the plurality of phase shifters includes n serially connected phase shifters. The second subset of phase shifters is coupled between the first input terminal and the second input terminal of the second phase interpolator.