Reference-Less Repeater Frequency Estimation Circuit
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Solution Overview
Problem
Current reference-less repeaters face challenges in adapting to wide frequency detection ranges and data rate flexibility, particularly with analog-only solutions consuming high power and digitally controlled circuits having narrow frequency detection ranges.
Innovation Solution
A frequency estimation circuit that measures edge-to-edge transitions in a data stream, categorizes these transitions into representative groups, and determines a frequency estimate using a processor, allowing for efficient frequency information propagation without external frequency references.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If analog-only frequency detection is used, then wide frequency detection range is achieved, but power consumption increases significantly
Solution Approach 1:
The patent replaces analog frequency detection mechanisms with a digital system that counts transitions in the input signal during a measurement interval. This digital approach substitutes complex analog circuitry with simpler digital counting logic, achieving wide frequency detection range while significantly reducing power consumption.
Solution Approach 2:
The patent uses a counter to create a digital representation (copy) of the frequency information by counting signal transitions. Instead of directly processing analog frequency signals, the system creates a digital count that represents the frequency, which can then be processed efficiently with minimal power consumption.
2Use of energy by moving object
If digitally controlled retiming circuits are used, then power consumption is reduced, but frequency detection range becomes narrow
Solution Approach 1:
The patent implements a dynamic frequency estimation system that adapts to different input frequencies by measuring transitions over a predetermined time interval. The system dynamically adjusts to various data rates including auto-negotiation rates, overcoming the narrow frequency detection range limitation of traditional digitally controlled circuits.
Solution Approach 2:
The frequency estimation circuit is designed to handle multiple frequency ranges and data rates universally. By counting transitions in a fixed time interval and using this count to control the retiming circuit, the system achieves both wide frequency detection range and low power consumption, making it suitable for various applications including auto-negotiation.
3Reliability
If external frequency references are used, then frequency stability is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent implements a self-service frequency control system where the retiming circuit uses the input signal itself to control its operation. The frequency estimation circuit measures transitions in the input signal and uses this information to automatically control the retiming, eliminating the need for external frequency references and reducing device complexity.
Solution Approach 2:
The patent extracts frequency information directly from the input signal by counting its transitions. Instead of relying on external frequency references, the system extracts the necessary frequency control information from the signal being processed, thereby eliminating external components and reducing overall device complexity.
Data Source
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Figure 3A~3B
AI summary
A frequency estimation circuit for a reference-less repeater circuit comprises an edge detector configured to measure time periods between edge-to-edge transitions in a data stream within a predetermined time interval, resulting in a plurality of edge-to-edge time periods; and a processor configured to categorize the plurality of edge-to-edge time periods into a plurality of representative groups, each representative group having a representative time period that is an integer multiple of a sampling unit time period; to determine a number of virtual transitions in the predetermined time interval based on the categorized plurality of edge-to-edge time periods and to determine a frequency estimate of the data stream based on the number of virtual transitions in the predetermined time interval.