ADC Signal Compression for Higher Small-Signal Resolution
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Solution Overview
Problem
Conventional analog-to-digital converters introduce significant quantization noise, especially for small signal amplitudes, due to equally sized intervals for both small and large signal values, and non-linear converters are complex and expensive.
Innovation Solution
A processing chain that applies a non-linear compressing function to the analog signal, followed by linear digitization, and then applies the inverse function to the digital samples, resulting in a digital signal with reduced quantization error by varying the granularity of quantizing steps based on signal amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If linear ADC with equally sized intervals is used, then device complexity is low, but measurement precision deteriorates for small signal amplitudes
Solution Approach 1:
The patent applies a non-linear compression function (such as logarithmic or power function) to transform the input signal before ADC conversion. This changes the parameter distribution of the signal, expanding small amplitude values and compressing large amplitude values, thereby achieving uniform quantization precision across different signal ranges while using a simple linear ADC.
Solution Approach 2:
The patent introduces a compression function as an intermediary component between the analog signal source and the linear ADC. This intermediary transforms the signal characteristics so that the simple linear ADC can achieve high precision measurement for both small and large signals, avoiding the need for complex non-linear ADC circuitry.
2Measurement precision
If non-linear ADC with variable interval quantization is used, then measurement precision for small signals is improved, but device complexity increases
Solution Approach 1:
The patent introduces a compression function as an intermediary component between the analog signal source and the linear ADC. This intermediary transforms the signal characteristics so that the simple linear ADC can achieve high precision measurement for both small and large signals, avoiding the need for complex non-linear ADC circuitry.
Solution Approach 2:
The patent applies a non-linear compression function (such as logarithmic or power function) to transform the input signal before ADC conversion. This changes the parameter distribution of the signal, expanding small amplitude values and compressing large amplitude values, thereby achieving uniform quantization precision across different signal ranges while using a simple linear ADC.
3Measurement precision
If non-linear compression function is applied before linear ADC, then measurement precision is improved, but device complexity is reduced
Solution Approach 1:
The patent applies a non-linear compression function (such as logarithmic or power function) to transform the input signal before ADC conversion. This changes the parameter distribution of the signal, expanding small amplitude values and compressing large amplitude values, thereby achieving uniform quantization precision across different signal ranges while using a simple linear ADC.
Solution Approach 2:
The patent introduces a compression function as an intermediary component between the analog signal source and the linear ADC. This intermediary transforms the signal characteristics so that the simple linear ADC can achieve high precision measurement for both small and large signals, avoiding the need for complex non-linear ADC circuitry.
Data Source
AI summary
Embodiments of the invention relate to a method and a corresponding circuit for digitizing an analog signal. Applying a nonlinear function to the signal, digitizing the signal and applying the inverse of the nonlinear function to the digital samples improve the digital samples.