Voltage Controlled Oscillator Amplitude Stability
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Solution Overview
Problem
Voltage controlled oscillators face the challenge of amplitude variance in output signals when adjusting control voltage, leading to increased phase jitter and phase noise, which negatively impacts the signal-to-noise ratio (SNR).
Innovation Solution
Incorporating a delay circuit with adjustable impedance elements and a control circuit in a ring oscillator, allowing for independent control of resistances to adjust oscillating frequency without altering the output signal amplitude, using a combination of digital and analog elements for coarse and fine-tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the control voltage is changed to adjust the oscillating frequency, then the oscillating frequency can be tuned, but the amplitude of the output signal will change accordingly
Solution Approach 1:
The control voltage is segmented into two independent components: a first control voltage for adjusting oscillating frequency and a second control voltage for stabilizing output amplitude. This segmentation allows frequency tuning without amplitude variation, resolving the contradiction between frequency adjustability and amplitude stability.
Solution Approach 2:
A voltage generator circuit acts as an intermediary between the control voltage input and the oscillation control. This circuit processes the control voltage to generate separate frequency-control and amplitude-control signals, enabling independent adjustment of frequency while maintaining stable amplitude through the mediator's signal separation function.
2Use of energy by moving object
If the amplitude of the output signal is smaller, then the device can operate with lower power, but the jitter and phase noise of the output signal will be larger
Solution Approach 1:
The invention changes the control parameter from direct voltage control to dual-voltage control with separate amplitude and frequency components. By maintaining a substantially constant amplitude through the second control voltage while adjusting frequency with the first control voltage, the system achieves low power consumption without sacrificing signal quality, as the amplitude stability prevents jitter and phase noise degradation.
3Reliability
If the amplitude of the output signal is larger, then the signal to noise ratio can be improved, but the power consumption will increase
Solution Approach 1:
The invention introduces dynamic control through two independently adjustable voltage components that adapt to different operating conditions. The first control voltage dynamically adjusts frequency while the second control voltage dynamically maintains optimal amplitude, enabling the system to achieve high signal-to-noise ratio when needed while consuming minimal power during normal operation, rather than requiring continuously high amplitude.
Data Source
AI summary
A delay circuit, which is included in a ring oscillator, comprises a current source for providing a current; a first circuit coupled to the current source for receiving an input signal and producing an output signal; a second circuit coupled to the current source and the first circuit; a first adjustable impedance element coupled to the first circuit; a second adjustable impedance element coupled to the second circuit; and a control circuit coupled to the first adjustable impedance element and the second adjustable impedance element for producing a first control signal to control a first resistance of the first adjustable impedance element and producing a second control signal to control a second resistance of the second adjustable impedance element; wherein the first adjustable impedance element includes at least one transistor operated in linear region, and the second adjustable impedance element also includes at least one transistor operated in linear region.