Oscillator Temperature Compensation With Slot-Based Memory Reduction
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Solution Overview
Problem
Existing methods for compensating temperature-related frequency drift in oscillators require significant memory resources to store data for a wide range of operating temperatures, which is costly and inefficient, especially in mobile receivers.
Innovation Solution
A method that dynamically collects and stores oscillator compensation data over a small region of the operating temperature range, using a series of temperature slots and bins, and applies these data to provide compensation for temperature-related frequency drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predetermined oscillator temperature-frequency transfer curve is used for compensation, then temperature compensation can be provided, but the approach cannot account for individual oscillator behaviour and aging effects
Solution Approach 1:
The patent applies preliminary action by creating and storing a look-up table mapping temperatures to compensation values during initial device calibration. This pre-computed table is then used during operation to provide temperature compensation without requiring real-time computation or external references.
Solution Approach 2:
The patent creates a copy of the oscillator's temperature-frequency characteristics in the form of a look-up table during calibration. This stored representation allows the system to retrieve compensation values quickly during operation without needing to access the actual oscillator or perform complex calculations.
2Reliability
If look-up tables are dynamically maintained by periodically measuring and recording ambient temperature and frequency offset, then aging effects are compensated, but relatively large amounts of data must be collected and stored
Solution Approach 1:
The patent segments the temperature range into discrete temperature slots, with each slot containing a limited number of measurement points. This segmentation allows the system to cover a wide temperature range while storing only a manageable amount of data in each slot, reducing overall memory requirements.
Solution Approach 2:
The patent uses partial action by measuring and storing data at specific temperature points within each slot rather than continuously across the entire temperature range. This selective sampling provides sufficient compensation data while minimizing the quantity of stored information.
3Measurement precision
If compensation data is collected over a wide range of operating temperatures with sufficient temperature resolution, then accurate compensation is achieved, but memory requirements present significant cost and overhead
Solution Approach 1:
The patent divides the temperature range into multiple slots, each covering a specific temperature interval. Within each slot, only a limited number of temperature points are measured and stored. This segmentation maintains adequate temperature resolution for accurate compensation while significantly reducing the total memory overhead compared to storing data across the entire temperature range with fine resolution.
Solution Approach 2:
The patent introduces a spatial dimension by organizing compensation data into a two-dimensional structure of temperature slots and measurement points within each slot. This dimensional organization allows efficient memory usage by storing data only where needed, rather than maintaining a complete high-resolution table across the entire temperature range.
Data Source
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AI summary
A method of compensating for the temperature related frequency drift of an oscillator. The method comprises using an external reference frequency signal to derive oscillator compensation data over a range of operating temperatures, storing the oscillator compensation data in a first table, and, for a given operating temperature, using the first table to obtain corresponding oscillator compensation data and applying that data to provide compensation for the temperature related frequency drift. The method further comprises defining, for the range of operating temperatures, a series of temperature slots each sub-divided into a series of temperature bins. The step of using an external reference frequency signal to derive oscillator compensation data over the range of operating temperatures comprises a) measuring an operating temperature and using the external reference frequency signal to determine oscillator compensation values for respective temperatures as the operating temperature varies; b) accumulating the determined oscillator compensation values in corresponding temperature bins of a second table; c) at spaced intervals in time, using the data accumulated in the temperature bins of the second table to determine or update the oscillator compensation data stored for one or more slots in the first table.