Single-Comparator AD Conversion for Wideband Noise Measurement
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Solution Overview
Problem
Flash AD converters require large circuit sizes and high power consumption due to numerous comparators, limiting their sampling frequency and resolution, making them unsuitable for applications with space and power constraints, such as spacecraft and battery-powered devices, especially for measuring wideband noise signals.
Innovation Solution
A one-bit AD converter with a single comparator that adjusts input voltage or determination voltage to change the ratio of output codes '1' and '0', allowing for various waveform information extraction through frequency calculations, enabling efficient conversion of wideband noise signals with low power consumption and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a flash AD converter with high sampling frequency is used, then the sampling frequency is improved, but the circuit size and power consumption are increased
Solution Approach 1:
The patent divides the high-resolution conversion task into multiple low-resolution conversion stages. Instead of using one complex high-resolution converter, it uses multiple simpler low-resolution converters sequentially, where each converter processes a portion of the signal and the results are combined to achieve the equivalent of high-resolution conversion. This segmentation reduces the complexity and power consumption of each individual converter while maintaining the overall high sampling frequency capability.
Solution Approach 2:
The patent employs dynamic adjustment of conversion parameters during operation. The system adaptively selects and switches between different conversion modes and parameters based on the input signal characteristics, allowing optimal performance across varying conditions. This dynamic approach enables the system to maintain high sampling frequency while adjusting resource usage to minimize circuit complexity and power consumption for each specific operating condition.
2Measurement precision
If a flash AD converter with high resolution is used, then the resolution is improved, but the circuit size and power consumption are increased
Solution Approach 1:
The patent segments the high-resolution conversion process into multiple low-resolution conversion stages. Each stage uses a simple low-resolution converter that requires minimal circuit resources. By combining the output codes from multiple sequential conversions and applying appropriate weighting and summation, the system achieves high-resolution measurement without requiring a single complex high-resolution converter, thus reducing overall circuit size and power consumption.
Solution Approach 2:
The patent uses multiple low-resolution conversions (excessive action) to achieve high resolution. Instead of using exactly the resolution needed in a single step, it performs multiple conversions with resolution slightly below the target, then combines them to exceed the target resolution. This approach trades the number of operations for reduced complexity per operation, resulting in lower overall circuit complexity while achieving the desired measurement precision.
3Measurement precision
If the number of comparators is increased, then the resolution is improved, but the power consumption is increased
Solution Approach 1:
The patent divides the comparison task across multiple time steps and multiple simple comparators rather than using many comparators simultaneously. Each comparator in each stage uses minimal power, and the sequential nature of the conversions allows power to be reused and managed efficiently. The combination of multiple low-power comparator outputs achieves high resolution without the exponential power consumption increase that would result from using a single high-resolution flash converter with many comparators.
4Speed
If a high sampling frequency is achieved, then the bandwidth measurement capability is improved, but the device size is increased
Solution Approach 1:
The patent implements high sampling frequency capability by segmenting the conversion process into multiple rapid low-resolution conversion cycles rather than using a single large high-resolution converter. This segmentation allows the use of smaller, faster circuit elements that can operate at higher frequencies. The compact design resulting from using multiple small converters instead of one large converter reduces the overall device size while maintaining high sampling frequency and bandwidth measurement capability.
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 AD converter effectively acquires multiple types of waveform information from a single comparator, achieving high-speed operation with low power consumption, suitable for measuring wideband noise signals, even in space-constrained environments like spacecraft, by shifting the determination voltage to alter the code frequency ratio.
Implementation Method 1
a comparator (10) that compares an input voltage of the analog signal to a determination voltage
Data Source
AI summary
Provided is an AD converter that is capable of converting a wideband noise signal of several GHz or more into a digital signal and that can be used even when an installation space and power supply are severely limited. The AD converter includes: a comparator (10) configured to compare an input voltage of an analog signal to a determination voltage; an adjustment unit (12) configured to shift at least one of the input voltage of the analog signal or the determination voltage; an encoder (11) configured to output time-series data of one bit based on a result of the comparison obtained by the comparator; a processing unit (13) configured to calculate a frequency of appearance of an output code included in the time-series data; and a control unit (14) configured to cause the adjustment unit to operate so that a result of the calculation obtained by the processing unit becomes a predetermined value.