Precise Time Tagging Over Imprecise Links
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Solution Overview
Problem
Precise timing and synchronization of events over an imprecise link between two unsynchronized chips is challenging, particularly in radio communication systems like GNSS receivers, where internal clocks are not locked, affecting demodulation efficacy.
Innovation Solution
A system and method involving a first terminal with a packetizer that creates a packetized data stream with event tags and a second terminal with counters to detect these tags, allowing precise timing by calculating the creation time of the packetized data stream based on counter values, enabling synchronization of internal clocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If event tags are embedded in packetized data streams at the first terminal, then precise time tagging of events is achieved, but the complexity of the data stream processing increases
Solution Approach 1:
The patent segments the time tagging function by separating the event detection at the first terminal from the time calculation at the second terminal. The first terminal only embeds tags without performing complex time calculations, while the second terminal receives tags and computes timestamps using its own clock and received tag information, dividing the processing complexity between two independent devices.
Solution Approach 2:
The event tag acts as an intermediary carrier that conveys timing information from the first terminal to the second terminal. The tag contains sufficient information (event occurrence indicator and associated data) for the second terminal to calculate the precise timestamp without requiring direct synchronization or complex processing at the first terminal.
2Measurement precision
If counters are used to count clock pulses at the second terminal, then accurate time calculation is achieved, but the synchronization requirement between terminals increases
Solution Approach 1:
The patent implements feedback by having the second terminal use the received event tag information to adjust and synchronize its own counter-based time calculation. The tag contains timing references that feed back to the second terminal, allowing it to accurately calculate timestamps even when clocks are not perfectly synchronized, thereby maintaining reliability without requiring strict synchronization.
Solution Approach 2:
The system changes the parameter approach from requiring synchronized clock frequencies to using relative time measurement. Instead of relying on identical clock rates, the second terminal measures the time difference between tag reception and its own counter reading, allowing accurate time calculation despite parameter variations in clock synchronization.
3Measurement precision
If the system calculates time based on counter values from both terminals, then precise event timing is achieved, but the processing time and computational load increase
Solution Approach 1:
The first terminal performs preliminary action by embedding the event tag with timing information at the moment of event occurrence. This pre-processing at the source eliminates the need for complex real-time calculations at the second terminal, as the tag already contains the necessary temporal data for accurate event timing reconstruction.
Solution Approach 2:
The patent uses copying by creating a simplified copy of the timing information in the event tag that can be transmitted to the second terminal. Instead of transmitting complete timing data or requiring full synchronization, the tag creates a condensed copy of essential timing parameters that enable the second terminal to reconstruct precise event times with minimal computational overhead.
Data Source
AI summary
A system for precise timing and synchronization of events is provided. The system includes a first terminal including one or more first counters and a packetizer configured to create a packetized data stream having one or more event tags. The system also includes a second terminal that includes one or more second counters and a depacketizer. The second counter(s) is/are configured to count clock pulses generated by a first clock of the first terminal at a first clock rate. The depacketizer is configured to receive the packetized data stream and detect the event tag(s). When the at least one event tag is detected, the second terminal calculates a time at which the first terminal created the packetized data stream based on a count value of the second counter(s) and a count value of the first counter(s) of the first terminal.