Single VCO Frequency Allocation for Multi-Band Communication
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Solution Overview
Problem
Existing communication devices face challenges with phase noise, limited reference frequency, and insufficient filtering in phase locked loops (PLLs) used for frequency synthesis, particularly when operating across multiple communication standards like IEEE 802.11a, 802.11b, and 802.11g, which require separate frequency bands.
Innovation Solution
A PLL architecture utilizing a single voltage controlled oscillator (VCO) to generate local oscillator signals for multiple frequency bands by employing a divide by two circuit and a divide by N circuit in the feedback loop, allowing for efficient frequency allocation across 802.11 standards, with the VCO operating in the range of 3.2 to 3.9 GHz to produce frequencies for 802.11a and 802.11b/g bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple VCOs are employed to generate local oscillation signals for different frequency bands, then frequency coverage for multiple communication standards is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent applies universality by designing a single VCO to perform multiple functions - generating local oscillation signals for both 802.11a (5 GHz) and 802.11b/g (2.4 GHz) frequency bands. The VCO is configured to operate across a wide frequency range (3.2-3.9 GHz) and through frequency multiplication techniques (divide-by-2 circuits and mixing), one oscillator serves multiple communication standards that would traditionally require separate VCOs, thereby reducing device complexity while maintaining broad frequency coverage
Solution Approach 2:
The patent merges the functions of multiple VCOs into a single unified oscillator system. By combining the 802.11a and 802.11b/g frequency generation paths through a single VCO with shared control logic and frequency synthesis circuits, the design reduces the total number of components while achieving multi-band operation capability
2Adaptability or versatility
If multiple VCOs are used for different frequency bands, then support for multiple communication standards is improved, but power consumption increases
Solution Approach 1:
The single VCO is designed to universally support multiple communication standards (802.11a, 802.11b, 802.11g) by operating across a wide frequency range and using frequency multiplication techniques. This eliminates the need for multiple separate VCOs, each consuming power independently, thereby reducing total power consumption while maintaining multi-standard support capability
Solution Approach 2:
By merging multiple frequency generation functions into a single VCO system with shared control and synthesis circuits, the patent reduces the total power consumption associated with operating multiple independent oscillators while maintaining the ability to support multiple communication standards
3Object-affected harmful factors
If PLL loop bandwidth is increased to improve noise rejection, then signal quality is improved, but phase noise performance may deteriorate
Solution Approach 1:
The patent applies parameter changes by systematically optimizing the PLL loop bandwidth to a specific value or range that achieves the best compromise between noise rejection and phase noise performance. By carefully selecting and adjusting the loop bandwidth parameter, the design maximizes signal quality while minimizing phase noise, rather than simply maximizing one parameter at the expense of the other
Data Source
AI summary
An apparatus and method to use a single voltage controlled oscillator (VCO) to generate frequencies to cover multiple frequency bands. The single VCO generates local oscillator signals for more than one frequency band of a communication standard or protocol, such as the IEEE 802.11 standard.