Variable-Time Optical Pulse Sampling for Low-Power Shape Reconstruction
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Solution Overview
Problem
Existing SAL pulse receivers face challenges in accurately measuring short-duration laser pulses with complex temporal shapes due to size, weight, and power constraints, and require improved sensitivity and temporal resolution for asynchronous, low-frequency pulsed signals with large dynamic range.
Innovation Solution
Implementing variable time sampling techniques that adjust the sampling rate based on changes in pulse amplitude, allowing for asynchronous sampling above a threshold, reducing power consumption and enhancing pulse shape reconstruction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fixed-rate sampling is used to accurately measure short-duration laser pulses, then temporal resolution is maintained, but power consumption increases and circuit size grows
Solution Approach 1:
The patent implements variable time sampling where the sampling rate dynamically adjusts based on pulse characteristics. During pulse events, the sampling rate increases to capture temporal details, while between pulses the sampling rate decreases to reduce power consumption. This dynamic adaptation resolves the contradiction between maintaining temporal resolution and reducing power usage.
Solution Approach 2:
The system changes the sampling rate parameter based on detected pulse amplitude and temporal characteristics. When a pulse is detected exceeding a threshold, the sampling rate increases to capture the pulse shape accurately; when no pulse is present, the sampling rate decreases. This parameter adaptation allows the system to maintain measurement precision only when necessary, reducing overall power consumption.
2Measurement precision
If higher sampling rates are used to capture complex pulse shapes, then pulse shape reconstruction accuracy improves, but power consumption and circuit complexity increase
Solution Approach 1:
The sampling rate is made dynamic rather than fixed, adjusting based on the presence and characteristics of detected pulses. During pulse events, high sampling rates capture complex temporal shapes; between pulses, lower rates reduce circuit activity. This dynamic approach maintains reconstruction accuracy when needed while simplifying circuit operation during idle periods.
Solution Approach 2:
The system employs periodic pulse detection and sampling activation rather than continuous high-rate sampling. The comparator triggers sampling events periodically based on pulse detection, allowing the circuit to operate at low complexity between events while maintaining high accuracy during pulse capture periods.
3Reliability
If continuous sampling is performed to capture all pulse events, then no pulses are missed, but power consumption increases significantly
Solution Approach 1:
Instead of continuous sampling, the system uses periodic pulse-triggered sampling activated by a comparator threshold detection. The sampling occurs periodically in response to detected pulse events rather than continuously, maintaining reliable pulse capture while dramatically reducing power consumption during idle periods when no pulses are present.
Solution Approach 2:
The system uses the detected pulse signal itself to trigger the sampling action. The comparator detects pulse amplitude and automatically activates the sampling circuit only when a pulse exceeds the threshold, making the system self-regulating and eliminating the need for continuous external sampling control, thereby reducing power consumption while maintaining detection reliability.
4Area of stationary object
If larger detector arrays are used to achieve wide field of view with high capacitance detectors, then field of view increases, but device size and complexity increase
Solution Approach 1:
The variable time sampling approach allows the system to use fewer detector elements effectively by concentrating sampling resources on detected pulse events. Rather than requiring large arrays to simultaneously capture all spatial and temporal information, the dynamic sampling focuses measurement effort on actual pulse occurrences, reducing the required detector array size while maintaining field of view coverage.
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
The asynchronous sampling method achieves a 90% reduction in power usage and reduces circuit size while providing more accurate pulse shape reconstruction, especially in low pulse repetition frequency environments.
Implementation Method 1
one or more photo-detecting elements and a comparing means
Data Source
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AI summary
Methods and apparatus for variable time sampling of optical pulses by a unit cell are disclosed. The methods may include detecting whether an amplitude of an optical pulse incident on one or more photo-detecting elements exceeds a sampling threshold, and while the pulse amplitude remains above the sampling threshold, iteratively sampling the optical pulse at a sampling rate that varies based on changes in the pulse amplitude.