Multi-Slope Ramp A/D Conversion for Lower Quantization Noise
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Solution Overview
Problem
Existing analog-to-digital converters using ramp signals with different slopes generate noise due to quantization errors.
Innovation Solution
A signal processing method that employs multiple ramp signals with varying slopes for A/D conversion, adjusting the slope ratios to minimize quantization errors and reduce noise, allowing for A/D conversion of analog signals to digital signals with different bit numbers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a ramp signal with different slopes is used for A/D conversion, then high dynamic range and high-speed drive are achieved, but noise is generated due to quantization error
Solution Approach 1:
The patent divides the A/D conversion process into multiple stages, performing first A/D conversion with a first ramp signal and second A/D conversion with a second ramp signal having a different slope ratio. This segmentation allows each conversion stage to operate with optimized parameters, reducing overall quantization error and noise while maintaining high conversion speed and dynamic range
Solution Approach 2:
The patent changes the slope ratio parameter of the ramp signal between different A/D conversion stages. By using a first ramp signal with a first slope ratio for the first conversion and a second ramp signal with a second slope ratio for the second conversion, the system optimizes the conversion process to reduce quantization error and noise while achieving high dynamic range and high-speed operation
2Measurement precision
If multiple ramp signals with different slopes are used for A/D conversion, then quantization errors are reduced, but device complexity increases
Solution Approach 1:
The patent employs a single ramp signal generation circuit that produces multiple ramp signals with different slope ratios, which are then used in different A/D conversion stages. This multi-functional approach improves conversion accuracy through multiple conversions with varying parameters while avoiding the need for separate dedicated circuits for each conversion type, thereby limiting the increase in device complexity
Data Source
AI summary
A signal processing method for converting analog signals to digital signals of different bit numbers using a sloped ramp signal includes first A/D conversion for converting an analog signal to a digital signal of a first bit number using a first ramp signal with a first slope or converting the analog signal to the digital signal of the first bit number using a second ramp signal with a second slope, and second A/D conversion for converting an analog signal to a digital signal of a second bit number using a third ramp signal with a third slope or converting the analog signal to the digital signal of the second bit number using a fourth ramp signal with a fourth slope, wherein a ratio of the second slope to the first slope is lower than a ratio of the fourth slope to the third slope.