PLL-Based Converter Synchronization Under Temperature Drift
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Solution Overview
Problem
Conventional high-speed converter systems, such as RFSoC devices and ADCs/DACs, face challenges in achieving accurate synchronization due to temperature variations, resulting in latency issues that limit data transmission frequency and are not sufficient for applications like digital beam forming in radar systems.
Innovation Solution
A temperature-compensated zero-delay phase-locked loop (PLL) is integrated into programmable logic within converter devices to align phases of reference and request signals, allowing for synchronization of sampling clock signals across multiple converter units, relaxing synchronization requirements from picoseconds to nanoseconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional synchronization methods are used with high-speed converters, then data transmission frequency can be increased, but synchronization accuracy deteriorates due to temperature variations causing latency drift
Solution Approach 1:
The patent changes the timing parameter from picosecond-level precision to nanosecond-level precision by using the PLL-generated request signal instead of relying on external sysref signal timing. This parameter change allows the system to maintain synchronization accuracy across temperature variations while supporting high-speed data transmission.
Solution Approach 2:
The temperature-compensated zero-delay PLL provides feedback mechanisms that automatically adjust for temperature-induced latency variations. The PLL continuously monitors and compensates for timing drift, ensuring that the request signal maintains proper phase relationship with the reference clock despite environmental changes.
2Measurement precision
If picosecond-level synchronization precision is required, then synchronization accuracy is improved, but system complexity and cost increase significantly
Solution Approach 1:
The patent introduces an intermediary PLL device that generates the request signal with proper timing characteristics. This intermediary component simplifies the overall system by providing built-in timing generation and temperature compensation, eliminating the need for complex external synchronization circuitry and reducing system complexity while maintaining nanosecond-level precision.
3Adaptability or versatility
If external sysref signal distribution is used for synchronization, then multiple converter units can be synchronized, but latency variations due to signal propagation deteriorate synchronization accuracy
Solution Approach 1:
The patent segments the synchronization function by having each converter unit generate its own request signal locally using the PLL and reference clock, rather than distributing a single external sysref signal. This segmentation eliminates propagation delay issues and ensures that each unit has accurate timing information without suffering from signal distribution latency variations.
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
This solution enables sample-accurate synchronization of high-speed converters, ensuring robust and cost-efficient synchronization across multiple devices, meeting the demands of digital beam forming applications by compensating for latency variations and eliminating the need for precise picosecond timing.
Implementation Method 1
a phase-locked loop, PLL, device (125) which is configured to align phases of the reference clock and the request signal
Implementation Method 2
temperature compensated zero-delay phase-locked loop (PLL) is integrated into programmable logic within converter devices to align phases
Data Source
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AI summary
An apparatus for synchronizing comprises at least one converter device (100) including multiple converter units (no) for performing multiple samplings steps using the sampling clock signals (250) and a programmable logic (120) with a phase-locked loop, PLL, device (125), the programmable logic (120) being configured to pre-process signals for or from the converter units (110). The apparatus further comprises a clock device (200) configured to generate the sampling clock signal (250) based on a reference clock (150) and to generate a system reference signal (260) based on a request signal (160). The request signal (160) is generated by the PLL device (125) with a same phase as the reference clock (150) to synchronize the multiple converter units (110).