Reference Clock Circuit Using a Controllable Oscillator
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Solution Overview
Problem
The high cost of crystal oscillators in mobile systems for generating precise clock signals for baseband chips is a significant concern, as they contribute to the Bill of Materials (BOM) cost and require additional printed circuit board (PCB) area.
Innovation Solution
A signal processing device and method that utilize a controllable oscillator, such as a voltage-controlled oscillator (VCO), to generate an oscillating signal, which is then transmitted through a conducting path to the signal processing chip, eliminating the need for a crystal oscillator and reducing BOM costs and PCB area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a crystal oscillator is used to generate precise clock signals for the baseband chip, then the stability and precision of the clock signal is improved, but the BOM cost and PCB area increase
Solution Approach 1:
The patent extracts the oscillation function from the baseband chip itself and places it in a separate controllable oscillator module. This allows the use of a cheaper oscillator while maintaining signal integrity through external transmission via conducting paths, resolving the contradiction between cost reduction and signal stability.
Solution Approach 2:
The patent introduces conducting paths as intermediaries to transmit the oscillating signal from the controllable oscillator to the baseband chip. This intermediary transmission path ensures signal stability while allowing the use of lower-cost oscillator components, thus resolving the cost-stability tradeoff.
2Measurement precision
If a crystal oscillator is used to generate precise clock signals, then the reference clock signal quality is improved, but the PCB area occupied increases
Solution Approach 1:
The patent segments the clock signal generation system into separate functional modules: a controllable oscillator module and a baseband chip module, connected via conducting paths. This segmentation allows for optimized component selection and reduced overall PCB footprint while maintaining signal quality.
Solution Approach 2:
The patent uses a controllable oscillator to generate an oscillating signal that is then transmitted to the baseband chip, effectively copying the function of a crystal oscillator without requiring the physical crystal oscillator component, thereby reducing PCB area while maintaining functional equivalence.
3Ease of manufacture
If a controllable oscillator is used instead of a crystal oscillator, then the BOM cost and PCB area are reduced, but the signal transmission stability may be affected
Solution Approach 1:
The conducting paths serve as controlled intermediaries that ensure stable signal transmission from the controllable oscillator to the baseband chip. These dedicated transmission paths compensate for the potentially lower inherent stability of controllable oscillators compared to crystal oscillators, maintaining signal integrity while achieving cost reduction.
Solution Approach 2:
The system employs feedback mechanisms through the conducting paths to monitor and adjust the oscillating signal transmission, ensuring that signal stability is maintained even when using a controllable oscillator instead of a crystal oscillator, thus resolving the reliability concern.
Data Source
AI summary
A signal processing device includes a signal processing chip and a conducting path. The signal processing chip includes: a first port capable of receiving a first oscillating signal; a second port capable of outputting a second oscillating signal derived from the first oscillating signal; and a third port. The conducting path is external to the signal processing chip and coupled to the second port and the third port, and the conducting path is capable of transmitting the second oscillating signal outputted from the second port to the third port.