FPGA Adjustable Clock with Delay-Line Jitter Reduction
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Solution Overview
Problem
Existing digital audio systems face challenges in providing a clock that is both accurately adjustable and has low jitter, often requiring specialized hardware chips and circuits that increase manufacturing costs and power consumption.
Innovation Solution
An adjustable clock implemented on an FPGA, utilizing a numerically-controlled frequency divider, a jitter-reduction circuit with a dynamically programmable delay line, an all-digital phase lock loop, and a software interface to adjust frequency and phase, allowing synchronization with external clocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If specialized clock synchronization circuitry is used to maintain synchronization between multiple digital audio devices, then synchronization accuracy is improved, but device manufacturing costs and power consumption increase
Solution Approach 1:
The patent combines multiple clock synchronization functions (phase detection, frequency division, delay adjustment) into a single integrated circuit block that can be implemented on a single chip. This merging of functions eliminates the need for multiple separate specialized hardware components, reducing both manufacturing costs and device complexity while maintaining synchronization accuracy through the integrated phase detector and delay line mechanisms
Solution Approach 2:
The circuit is designed to perform multiple clock synchronization functions simultaneously - it can detect phase differences, adjust delay, divide frequencies, and synchronize multiple audio devices. This multi-functional design allows a single circuit to replace what would traditionally require multiple specialized components, reducing overall system complexity while maintaining reliable synchronization across the audio device network
2Reliability
If multiple specialized hardware components are used for clock synchronization, then synchronization capability is improved, but power consumption increases
Solution Approach 1:
By merging multiple synchronization functions into a single integrated circuit, the patent reduces the total power consumption compared to using multiple separate active components. The integrated design allows for more efficient power management and reduces the overhead associated with multiple independent hardware blocks, while still providing real-time synchronization capability through the combined phase detector and delay adjustment mechanisms
3Stability of the object's composition
If traditional clock adjustment methods are used, then frequency stability is improved, but adjustability and software control capability are limited
Solution Approach 1:
The patent implements dynamic, software-controllable adjustment of clock phase and frequency through a programmable delay line and controllable frequency divider. These dynamic components allow the system to adapt clock parameters in real-time based on software commands, while the underlying circuit architecture maintains frequency stability through controlled adjustment mechanisms rather than uncontrolled variations
Solution Approach 2:
The system enables software-controlled changes to critical clock parameters including phase offset, frequency division ratio, and delay time. By allowing dynamic modification of these parameters through software while maintaining controlled adjustment mechanisms, the system achieves both adaptability for different application requirements and stability for reliable audio synchronization
4Adaptability or versatility
If a clock is designed to be highly adjustable with multiple features, then versatility is improved, but jitter performance deteriorates
Solution Approach 1:
The patent uses a dynamically programmable delay line that can adjust phase and frequency in real-time while maintaining low jitter performance. The dynamic adjustment capability allows for arbitrary frequency and phase settings, and the controlled architecture of the delay line ensures that these adjustments do not introduce excessive jitter, thus maintaining both versatility and reliability
Data Source
AI summary
An adjustable clock that may be implemented on a field-programmable gate array (FPGA). The adjustable clock may be highly accurate and stable, and may be adjustable in response to software commands. The adjustable clock may be configured to generate a clock signal that is synchronized in frequency and/or phase with a clock that is external to the FPGA, such as a Precision Time Protocol (PTP) clock. The FPGA may implement the adjustable clock with a number of elements as programmable logic, including a numerically-controlled frequency divider, a multi-tap delay line, logic configured to dynamically select, for each clock pulse, a delay of the multi-tap delay line, and a feedback loop to control the numerically-controlled frequency divider.