Forward Divider Clock Generator for Wide-Range Frequency and Phase
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Solution Overview
Problem
Conventional voltage-controlled oscillators (VCOs) and phase-lock loops (PLLs) are limited in generating periodic signals over a wide range of frequencies, requiring complex and expensive solutions for applications needing varied frequency and phase signals.
Innovation Solution
A forward divider circuit with a divider chain and retimer circuits that adjust the frequency and phase of output clock signals by presetting divider circuits and using retimer signals to synchronize transitions, allowing for generation of signals over a wide frequency range and multiple phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single VCO is used to generate periodic signals, then the circuit is simple and uses little circuitry, but the frequency range is limited
Solution Approach 1:
The frequency range is segmented into multiple bands, with each VCO handling a specific frequency range. The system divides the overall frequency requirement into manageable segments that can be covered by individual VCOs operating at different center frequencies.
Solution Approach 2:
Multiple VCOs are used where each oscillator serves the universal function of generating periodic signals, but each is tuned to a different frequency range. This multi-functional approach allows the system to cover a wide overall frequency range while maintaining the simplicity of individual VCO circuits.
2Adaptability or versatility
If a bank of VCOs is used to cover a wide frequency range, then the frequency coverage is improved, but the circuit becomes complex and expensive
Solution Approach 1:
The frequency range is segmented into multiple bands, with each VCO handling a specific frequency range. The system divides the overall frequency requirement into manageable segments that can be covered by individual VCOs operating at different center frequencies.
Solution Approach 2:
The system dynamically selects which VCO to use based on the desired output frequency. A frequency detection circuit identifies the target frequency range and automatically activates the appropriate VCO, providing adaptive frequency coverage without requiring all VCOs to operate simultaneously.
3Ease of operation
If the frequency of a VCO is varied by changing the control voltage magnitude, then the frequency can be adjusted, but the adjustment range is limited
Solution Approach 1:
Multiple VCOs are used where each oscillator serves the universal function of generating periodic signals, but each is tuned to a different frequency range. This multi-functional approach allows the system to cover a wide overall frequency range while maintaining the simplicity of individual VCO circuits.
Solution Approach 2:
The system dynamically selects which VCO to use based on the desired output frequency. A frequency detection circuit identifies the target frequency range and automatically activates the appropriate VCO, providing adaptive frequency coverage without requiring all VCOs to operate simultaneously.
Data Source
AI summary
A signal generator produces an output clock signal by coupling an input clock signal through a plurality of divider circuits each of which is formed by a toggling flip-flop. The frequency of the output clock signal is adjusted by selecting the flip-flop to which the input clock signal is coupled. Retimer flip-flops may be coupled between adjacent flip-flips to resynchronize the signal being coupled through the flip-flops. Each of the retimer flip-flops receives a respective signal from the output of an upstream flip-flop at its data input, and it receives the input clock signal at its clock input. The flip-flop then applies the signal to a downstream flip-flop in synchronism with the input clock signal. The final two flip-flops through which the input signal is coupled may be preset to various states to set the phase of the output clock signal to one of four phases.