Quartz Oscillator Preheating for RF Frequency Drift Control
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Solution Overview
Problem
Electronic devices with quartz crystal oscillation circuits face frequency drift issues due to temperature increases when the power amplifier is enabled, leading to deviations from the desired central frequency, particularly problematic during initial operation.
Innovation Solution
Implementing a delay between the enabling of the power amplifier and the passage of signals to the antenna, using a control circuit to manage this delay based on temperature measurements, and controlling the capacitance of variable capacitors to reduce frequency drift, while also preheating the quartz crystal to stabilize its temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the power amplifier is enabled to transmit RF signals, then the transmission function is activated, but the temperature of the quartz crystal increases causing frequency drift
Solution Approach 1:
The patent applies preliminary action by enabling the power amplifier before enabling the transmission function. This allows the PA to pre-heat the quartz crystal, stabilizing its temperature before actual signal transmission begins, thereby preventing frequency drift during operation
Solution Approach 2:
The patent implements periodic action through a delay mechanism that controls when the transmission function is activated relative to the power amplifier. By introducing a controlled time delay, the system periodically activates transmission only after temperature stabilization, ensuring frequency stability while maintaining transmission capability
2Speed
If the passage of signal to antenna is enabled immediately, then transmission starts without delay, but frequency drift occurs due to temperature increase
Solution Approach 1:
The system performs preliminary action by activating the power amplifier in advance before enabling signal passage to the antenna. This pre-heating phase stabilizes the quartz crystal temperature, ensuring frequency accuracy is maintained when transmission actually begins
Solution Approach 2:
The patent introduces an intermediary delay mechanism that mediates between the power amplifier activation and signal transmission to antenna. This intermediary control element ensures that signal passage is delayed until temperature stabilization occurs, maintaining frequency accuracy without permanently slowing transmission
3Reliability
If a delay is introduced between power amplifier enabling and signal passage, then frequency drift is reduced, but transmission is delayed
Solution Approach 1:
The delay is applied strategically as a preliminary action only during initial operation to stabilize frequency. Once the quartz crystal reaches thermal equilibrium, normal transmission proceeds without further delays, minimizing overall time loss while ensuring frequency stability during the critical startup phase
Solution Approach 2:
The delay mechanism operates periodically only when needed - specifically during transitions from off to on states. During steady-state operation, no delay is applied, thus minimizing time loss while maintaining frequency stability during the critical moments when temperature changes occur
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
This approach effectively reduces frequency drift during the initial period of operation, ensuring the frequency remains within acceptable thresholds without modifying the existing hardware, thus maintaining stable signal transmission.
Implementation Method 1
a quartz crystal is often used in oscillation circuits. Indeed, a feature of quartz crystals is that they generate relatively stable oscillations when receiving an electric voltage
Implementation Method 2
the device comprises a heater configured to increase the temperature of the quartz
Data Source
AI summary
An embodiment of the present disclosure relates to a device comprising an electronic circuit; an oscillation circuit comprising a quartz crystal, configured to provide a clock signal to the electronic circuit; and a heater configured to increase the temperature of the quartz crystal.