Single-VCO UWB Synthesizer With Divider Bank Frequency Coverage
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Solution Overview
Problem
Conventional frequency synthesizers for ultra-wideband (UWB) applications require multiple voltage-controlled oscillators (VCOs), leading to increased complexity, size, and cost, while using a single VCO with a large tuning range compromises performance.
Innovation Solution
A frequency synthesizer architecture utilizing a single VCO with a limited tuning range (less than 35%) in combination with a divider bank and multiplexer to generate multiple UWB frequencies, achieving at least 64% frequency coverage without multiple VCOs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple VCOs are used to cover different UWB frequencies, then frequency coverage is improved, but device complexity and size increase
Solution Approach 1:
A single VCO is designed to perform multiple functions by generating different output frequencies through a divider bank with multiple division ratios. The VCO operates at a fixed high frequency while the divider bank selectively divides the frequency to produce different UWB channel frequencies, allowing one VCO to replace what would traditionally require multiple VCOs.
Solution Approach 2:
A divider bank is introduced as an intermediary component between the single VCO and the output. This divider bank contains multiple parallel divider branches with different division ratios, acting as a mediator that transforms the single high-frequency VCO output into multiple lower-frequency UWB signals without requiring multiple VCOs.
2Adaptability or versatility
If a single VCO with large tuning range is used to cover wide spectrum, then frequency coverage is improved, but phase noise performance deteriorates
Solution Approach 1:
Instead of changing the VCO's tuning range parameter, the invention changes the system's frequency selection mechanism by using a divider bank with multiple fixed division ratios. The VCO maintains a narrow, stable tuning range for optimal phase noise performance, while the divider bank provides the frequency variability needed for wide spectrum coverage.
Solution Approach 2:
The frequency coverage function is segmented from the VCO and assigned to the divider bank. The VCO is responsible only for generating a stable high-frequency signal with narrow tuning range, while the divider bank segments the frequency spectrum into multiple discrete channels through different division ratios, achieving wide coverage without compromising VCO performance.
3Adaptability or versatility
If a single VCO with large tuning range is used to cover wide spectrum, then frequency coverage is improved, but startup conditions are compromised
Solution Approach 1:
The invention changes the approach from adjusting VCO tuning range to adjusting divider ratios. The VCO operates with a fixed, narrow tuning range that ensures reliable startup conditions, while the divider bank's division ratios are changed to achieve different output frequencies. This parameter substitution maintains VCO stability while providing frequency versatility.
Solution Approach 2:
The frequency adaptation function is segmented away from the VCO and placed in the divider bank. This segmentation allows the VCO to maintain optimal startup conditions with a narrow tuning range, while the divider bank handles the frequency multiplication/division to achieve wide spectrum coverage across UWB channels.
Data Source
AI summary
The present disclosure relates to a frequency synthesizer capable of generating a full spectrum for ultra-wideband applications by utilizing a single voltage-controlled oscillator (VCO). The disclosed frequency synthesizer includes a phase-frequency detector (PFD), a charge pump (CP), a VCO, a feedback divider, and a divider bank. The PFD, the CP, the VCO, and the feedback divider are coupled in series in a closed loop, while the divider bank follows the VCO and is not included in the closed loop. Herein, the VCO has a tuning range less than 35%. The divider bank includes two or more divider branches parallel to each other, each of which is configured to provide a different division ratio. An oscillating spectrum of the VCO and division ratios of the two or more divider branches are selected such that the divider bank is capable of providing a continuous spectrum with at least a 64% frequency coverage.