VCO Offset Compensation for Accurate Open-Loop Frequency Synthesis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing signal synthesis devices struggle to correct frequency offsets during open loop operation, especially in low-power modes, leading to inaccurate frequency output due to manufacturing processes and environmental changes like temperature and humidity.
Innovation Solution
A signal synthesis apparatus and method that includes a voltage-controlled oscillator (VCO), an energy storage unit, a VCO input selector, and a digital controller, which calculates and compensates for frequency offsets by switching between closed and open loop modes, adjusting offset voltages, and using modulation control signals to ensure accurate frequency output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the PLL circuit operates in open loop mode for low-power operation, then energy consumption is reduced, but frequency accuracy deteriorates due to offset
Solution Approach 1:
The patent applies preliminary action by measuring and storing the open-loop offset during closed-loop operation before actual open-loop operation begins. The offset measurement unit measures the frequency difference between open-loop and closed-loop modes in advance, and the controller stores this offset value to be used during low-power open-loop operation, thereby maintaining frequency accuracy without continuous power consumption.
Solution Approach 2:
The patent changes the control parameter by adjusting the VCO control voltage based on the measured offset. The controller adds or subtracts the stored offset value from the VCO control voltage to compensate for frequency deviations during open-loop operation, thereby maintaining accurate frequency output while operating in low-power mode.
2Measurement precision
If offset correction is implemented continuously to maintain frequency accuracy, then frequency accuracy is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic action by performing offset measurement and correction only when needed - specifically during initial closed-loop operation and when switching between modes. The controller determines whether offset correction is necessary based on operational state, rather than continuously correcting, thereby reducing energy consumption while maintaining frequency accuracy when required.
Solution Approach 2:
The system performs self-service by automatically measuring, storing, and applying offset compensation without external intervention. The offset measurement unit and controller work autonomously to detect frequency deviations and adjust the VCO control voltage accordingly, eliminating the need for manual calibration or continuous external monitoring.
3Device complexity
If manufacturing process variations and environmental changes are not compensated, then device complexity is reduced, but frequency stability deteriorates
Solution Approach 1:
The patent implements feedback by using the offset measurement unit to continuously monitor frequency deviations caused by manufacturing variations and environmental changes. The measured offset is fed back to the controller, which adjusts the VCO control voltage to compensate for these variations, thereby maintaining frequency stability without requiring complex hardware modifications.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables accurate frequency output correction in low-power open loop operations, addressing manufacturing and environmental-induced deviations, thereby enhancing the reliability and efficiency of frequency synthesis in IoT devices and wireless communication systems.
Implementation Method 1
a voltage-controlled oscillator (VCO) that generates an output signal having a frequency corresponding to an input voltage
Implementation Method 2
an energy storage unit that stores energy using an input voltage and outputs a voltage based on the stored energy
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
Disclosed is technology related to a signal synthesis apparatus that corrects an offset between a closed loop and an open loop to output a frequency-modulated signal. The signal synthesis apparatus includes a VCO configured to output a frequency signal in response to an input voltage, an energy storage unit configured to output a voltage using stored energy, a VCO input selector configured to connect the VCO to input of the energy storage unit in the case of a closed loop mode and connect the VCO to output of the energy storage unit in the case of an open loop mode, and a digital controller configured to control an operation mode of the VCO input selector and transmit an offset control signal for adjusting an offset of a voltage output from the energy storage unit to the energy storage unit.