VCO Signal Synthesis with Open-Loop Frequency Offset Compensation
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Solution Overview
Problem
Existing signal synthesis devices fail to correct frequency offsets during open loop operation, particularly in low-power scenarios, and are susceptible to deviations 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 to adjust operation modes and offset voltages, using frequency and modulation control signals to correct frequency deviations.
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 offset occurs due to lack of closed loop correction
Solution Approach 1:
The system performs frequency offset calibration in advance during closed loop mode before switching to open loop mode. The calibrated offset value is stored and applied during open loop operation, allowing the system to maintain frequency accuracy without continuous closed loop correction, thus reducing energy consumption while preserving frequency precision.
2Measurement precision
If offset correction is implemented during open loop operation, then frequency accuracy is improved, but device complexity increases
Solution Approach 1:
The offset correction functionality is merged into the existing loop filter circuit by adding an offset voltage input terminal. The offset correction unit integrates with the voltage-controlled oscillator and energy storage unit, sharing common circuit elements. This merging approach enables offset correction during open loop operation without requiring separate dedicated correction circuits, thus improving frequency accuracy while minimizing the increase in device complexity.
3Stability of the object's composition
If continuous closed loop operation is maintained for accurate frequency, then frequency stability is improved, but energy consumption increases
Solution Approach 1:
The system dynamically switches between closed loop and open loop modes based on operational requirements. During initialization and calibration phases, closed loop mode provides accurate frequency stabilization. During normal low-power operation, the system transitions to open loop mode using pre-calibrated offset values, maintaining frequency stability while significantly reducing energy consumption. The energy storage unit maintains voltage levels to ensure stable VCO operation during open loop mode.
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 by correcting open loop offsets, supporting low-power operation and adapting to environmental changes, ensuring stable and fast frequency modulation.
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
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.