Multiphase Signal Generator with Passive Phase Shifting
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Solution Overview
Problem
Existing signal generators for communications systems face high power consumption and increased phase asymmetry and jitter due to the use of high-speed frequency dividers and delay elements for generating multiple phases of a clock signal.
Innovation Solution
A multiphase signal generator circuit that includes a passive quadrature phase shifter and a phase interpolation circuit, utilizing a configurable quadrature phase shifter with variable capacitors and digital control for precise phase adjustment, to generate multiple output signals with controlled phase shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate oscillators are used for each output signal, then signal independence and reliability are improved, but device complexity and cost increase
Solution Approach 1:
The single oscillator is segmented into multiple phase outputs (I, Q, D, S, and complementary phases) that function independently while sharing a common frequency source. This segmentation allows signal independence without requiring separate oscillators for each output.
Solution Approach 2:
A single oscillator circuit performs multiple functions by generating five different phase signals simultaneously. The oscillator serves as a universal source for all quadrature and differential signals needed by the modulator, eliminating the need for multiple dedicated oscillators.
2Reliability
If multiple oscillators are used to generate quadrature signals, then signal quality and independence are improved, but power consumption and device complexity increase
Solution Approach 1:
Multiple oscillator functions are merged into a single oscillator circuit. The patent combines quadrature generation, differential signal generation, and phase splitting into one integrated oscillator that produces all required signals simultaneously, reducing total power consumption compared to multiple separate oscillators.
Solution Approach 2:
The single oscillator is designed as a multi-functional device that generates I, Q, D, S, and complementary phases with high signal quality. This universal oscillator replaces multiple specialized oscillators, maintaining signal quality while reducing power consumption through shared circuitry.
3Device complexity
If a single oscillator is used for all output signals, then device complexity and power consumption are reduced, but signal independence and reliability deteriorate
Solution Approach 1:
The oscillator output is segmented into multiple independent phase channels (I, Q, D, S) with complementary signals. Each channel maintains signal independence through dedicated phase splitting and buffering, ensuring reliability while sharing a common frequency source.
Solution Approach 2:
Phase splitters and buffers act as intermediaries between the single oscillator source and the multiple output channels. These intermediary circuits ensure signal independence and reliability by properly isolating and conditioning each phase output while maintaining synchronization to the common oscillator.
4Device complexity
If traditional oscillators are used, then circuit simplicity is maintained, but generation of multiple quadrature signals with precise phase relationships becomes complex
Solution Approach 1:
The oscillator circuit is designed as a universal signal generator that inherently produces precise quadrature relationships (90-degree phase differences) and differential phases (180-degree phase differences) through its multi-functional architecture, maintaining circuit simplicity while achieving high phase precision.
Solution Approach 2:
The oscillator uses parameter changes in the phase splitting network to generate precise phase relationships. By controlling the phase splitting parameters, the circuit achieves accurate quadrature and differential phase outputs without complex external phase adjustment mechanisms.
Data Source
Figure 1A~1B
Figure 2A
Figure 2B
AI summary
MULTIPHASE SIGNAL GENERATORAn apparatus which includes a multiphase signal generator circuit. The multiphase signal generator circuit is configured to receive as input a complementary analog signal having a fundamental frequency, and generate a plurality of output complementary analog signals. Each output complementary analog signal comprises the same fundamental frequency as the input complementary analog signal, and wherein each output complementary analog signal comprises a different phase.