Sensor Timing Buffer for Low-Jitter Asynchronous Data Readout
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Solution Overview
Problem
Current sensors face issues with time jitter and latency due to mismatches between output data rate and read-out data rate, leading to impaired accuracy in data fusion and increased power consumption, especially when handling multiple sensors.
Innovation Solution
Incorporating a timer unit in the digital back end of the sensor to provide time information, allowing the control unit to accurately determine the age of sampled data and estimate the real output data rate, thereby reducing jitter and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the read-out data rate is increased to reduce jitter, then the average jitter is reduced, but the power consumption of the control unit increases significantly
Solution Approach 1:
The sensor performs preliminary timing measurements and stores the actual sampling times in a buffer before the control unit reads the data. This allows the control unit to retrieve pre-calculated time information without needing to increase its read-out rate, thus reducing power consumption while maintaining time measurement precision.
Solution Approach 2:
A timing buffer or register acts as an intermediary between the sensor's sampling operation and the control unit's read-out operation. This intermediary stores the time information generated by the sensor, allowing the control unit to access accurate timing data without needing to synchronize its read-out rate with the sensor's sampling rate, thereby reducing power consumption.
2Measurement precision
If the output data rate is increased to reduce jitter, then the average jitter is reduced, but noise on the sensor data increases and the complexity of the digital back end increases
Solution Approach 1:
The timing function is segmented from the main data processing path in the digital back end. A dedicated timer unit independently records sampling times while the main processing path continues at the original output data rate. This segmentation allows precise timing measurement without increasing the overall output data rate or complicating the main data processing architecture.
Solution Approach 2:
A separate timer unit acts as an intermediary component that independently tracks sampling times without affecting the main data processing pipeline. This intermediary timing mechanism provides precise time information while allowing the digital back end to maintain its original complexity level and output data rate.
3Adaptability or versatility
If the control unit reads out data asynchronously from the sensor, then the control unit can operate independently, but time jitter is introduced between data generation and read-out
Solution Approach 1:
The sensor provides feedback about the actual sampling times to the control unit through the timing buffer. This feedback mechanism allows the control unit to operate asynchronously while still receiving accurate timing information, enabling it to compensate for time jitter in its processing and maintain time synchronization accuracy.
Solution Approach 2:
A timing buffer serves as an intermediary that decouples the asynchronous operations of the sensor and control unit. The buffer stores precise timing information generated by the sensor, allowing the control unit to read data at its own pace while still having access to accurate time stamps for synchronization purposes.
Data Source
AI summary
A sensor includes: a detection element; an analog front end; a digital back end, the digital back end being connected to a control unit via a digital interface, and the sensor providing sampled data in the digital back end; and a timer unit for providing pieces of time information of the sampled data in the digital back end which the control unit is able to access via the digital interface.