Programmable Feedback Divider Circuit for Accurate Frequency Verification
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Solution Overview
Problem
Existing frequency determination systems, particularly those using frequency mixers and phase locked oscillators, suffer from ambiguity in determining the correct output frequency due to lack of an independent onboard frequency determination mechanism, leading to inaccurate frequency verification in applications like RADAR and telecommunications.
Innovation Solution
A frequency verification circuit and method utilizing a phase frequency difference detector, voltage controlled crystal oscillator, and programmable feedback dividers to determine the frequency component of an input signal, allowing for independent and accurate frequency verification without prior knowledge of the signal's frequency composition, and incorporating a resolution bandwidth control circuit to adjust the range of locking frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency mixers and phase locked oscillators are used for frequency determination, then frequency verification capability is achieved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the essential frequency determination function from complex frequency mixers and phase locked oscillators, implementing it through a simplified phase frequency difference detector that directly compares phase and frequency differences between input and feedback signals, eliminating unnecessary components while maintaining verification accuracy
Solution Approach 2:
The patent replaces expensive, complex frequency determination components with a cost-effective implementation using a simple phase frequency difference detector, voltage controlled crystal oscillator, and programmable feedback dividers, achieving the same functional capability at reduced cost and component count
2Measurement precision
If frequency mixers and phase locked oscillators are used, then frequency determination is possible, but the system lacks independent onboard frequency determination capability leading to ambiguity
Solution Approach 1:
The patent implements a feedback mechanism where the voltage controlled crystal oscillator generates an output signal that is divided by programmable feedback dividers and fed back to the phase frequency difference detector, creating an independent onboard frequency determination system that verifies the correct frequency without external reference
Solution Approach 2:
The system performs self-verification by using its own output signal (divided through feedback dividers) as the reference for frequency determination, enabling independent onboard frequency determination without relying on external frequency sources or complex external verification equipment
3Adaptability or versatility
If a fixed feedback divider is used, then the circuit is simple, but it cannot verify multiple different test frequencies
Solution Approach 1:
The patent transforms the static feedback divider into a dynamic, programmable component that can be configured with different division ratios through digital control signals, enabling the same hardware to adaptively verify multiple different test frequencies by changing the feedback division ratio based on the expected input frequency
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate and independent frequency determination with reduced cost, capable of verifying the correct output frequency in systems and identifying frequency components, improving upon existing methods by providing a low-cost, low-component-count solution for frequency verification and spectrum analysis.
Implementation Method 1
a phase frequency difference detector for determining a difference in phase and frequency between the input signal and a feedback signal and for providing a control signal based on the detected difference
Implementation Method 2
a voltage controlled crystal oscillator for producing an output signal based on the control signal
Implementation Method 3
a feedback loop including a feedback divider for frequency dividing the output signal by a factor R to produce the feedback signal
Data Source
AI summary
Circuits and methods for identifying or verifying frequencies are disclosed herein. A frequency verification circuit comprises: an input port for receiving an input signal; a phase frequency difference detector for determining a difference in phase and frequency between the input signal and a feedback signal and for providing a control signal based on the detected difference; a voltage controlled crystal oscillator for producing an output signal based on the control signal; and a feedback loop including a feedback divider for frequency dividing the output signal by a factor R to produce the feedback signal, the feedback divider being programmable to a plurality of values of the factor R to correspond to a plurality of different test frequencies.