Dual Oscillator Architecture for GPS and Cellular Integration
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Solution Overview
Problem
Current communications systems that integrate GPS and cellular phone functionality face challenges in achieving accurate GPS system clock signals due to shared oscillators, leading to uncertainties and performance issues, particularly when switching between GSM base stations and requiring complex frequency compensation.
Innovation Solution
The system employs two oscillators, one low-cost and one high-precision, with a cross-referencing technique to determine precise frequencies for each circuit, eliminating the need for a single shared oscillator and reducing production costs while maintaining optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single oscillator is shared between GPS receiver and cellular phone circuitry, then cost is reduced, but frequency accuracy and positioning performance deteriorate
Solution Approach 1:
The system segments the oscillator function by using two separate oscillators: a low-cost oscillator for cellular phone circuitry and a high-precision oscillator for GPS circuitry. This segmentation allows each oscillator to be optimized for its specific function, with the high-precision oscillator ensuring accurate frequency for positioning while the low-cost oscillator serves the cellular functions, thereby resolving the contradiction between cost reduction and frequency accuracy.
Solution Approach 2:
The system applies local quality by providing different oscillator quality levels to different circuitry components. The GPS receiver circuitry receives a high-precision clock signal with accurate frequency, while the cellular phone circuitry uses a standard low-cost oscillator. This localized quality differentiation ensures that the critical positioning function receives high-frequency accuracy without requiring the entire system to use expensive oscillators.
2Adaptability or versatility
If frequency compensation is implemented to accommodate shared oscillator, then compatibility is improved, but system complexity increases
Solution Approach 1:
The system extracts the frequency compensation function from the hardware architecture and implements it through a frequency determination module that calculates the actual frequency of the high-precision oscillator. By taking out the complex frequency adjustment mechanisms and replacing them with a computational approach that determines frequency based on timing relationships, the system maintains compatibility while reducing hardware complexity.
3Measurement precision
If a high-precision oscillator is used for GPS, then positioning accuracy is improved, but cost increases
Solution Approach 1:
The system segments the oscillator requirements by allocating a high-precision oscillator specifically to the GPS receiver circuitry where positioning accuracy is critical, while using a low-cost oscillator for the cellular phone circuitry. This segmentation ensures that the expensive high-precision component is used only where necessary for accurate positioning, rather than being required for the entire integrated device.
Solution Approach 2:
The system applies local quality by providing high-precision oscillation only to the GPS circuitry portion of the integrated device, while the cellular circuitry uses standard-quality oscillators. This localized application of high quality ensures that positioning accuracy is improved without requiring the entire system to use expensive high-precision oscillators, thereby controlling overall cost.
Data Source
AI summary
A communications system includes a first oscillator for producing a first clock signal; a second oscillator for producing a second clock signal; and a secondary circuit coupled to the first oscillator and the second oscillator for determining a second oscillation frequency corresponding to a frequency of the second clock signal; the second oscillation signal being determined according to the first clock signal, the second clock signal, and a first oscillation frequency corresponding to a frequency of the first clock signal.