Non-linear Amplifier Stage for Electro-optical Distance Sensor Dynamic Range
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Solution Overview
Problem
Electro-optical range finders face challenges in achieving high dynamic range and measurement accuracy due to varying target reflectivity and distance, leading to signal saturation and noise issues, which complicates calibration and requires multiple operating modes.
Innovation Solution
An electro-optical range finder with a non-linear amplifier stage that adjusts amplification based on signal amplitude, allowing for amplitude dynamic compression and numerical compensation to restore a linear representation of the received signal, enabling detection of a wider intensity range without changing operating modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear amplifier stage is used to amplify received optical signals, then the amplification is simple and predictable, but the dynamic range of detectable light intensity is limited due to signal saturation at high intensities and noise dominance at low intensities
Solution Approach 1:
The patent applies parameter changes by making the amplification factor variable rather than constant. The amplifier stage dynamically adjusts its gain based on the input signal amplitude, transitioning from a linear amplifier with fixed parameters to a non-linear amplifier with adaptive parameters. This allows the system to handle both weak and strong signals within a single operating mode, expanding the detectable dynamic range without requiring multiple calibration sets.
Solution Approach 2:
The invention implements dynamics by introducing a time-varying amplification factor that automatically adapts to changing signal conditions. The amplifier transitions from a static, linear gain stage to a dynamic, non-linear stage that responds to signal amplitude variations. This dynamic behavior enables the system to maintain optimal signal-to-noise ratio across varying target reflectivities and distances without manual intervention or mode switching.
2Measurement precision
If multiple operating modes are used to cover different target reflectivities and distances, then the measurement accuracy is maintained across various conditions, but the number of calibration parameters and device complexity increases
Solution Approach 1:
The patent applies universality by designing a single amplifier stage that performs the function of multiple dedicated amplifiers would normally be required. The non-linear amplifier with adaptive gain replaces multiple linear amplifiers with fixed gain stages, each optimized for specific signal intensity ranges. This universal amplifier maintains measurement precision across all target conditions while eliminating the need for multiple operating modes and their associated calibration parameters.
Solution Approach 2:
The invention applies inversion by reversing the conventional approach to handling dynamic range. Instead of using multiple linear amplifiers with different fixed gain values and switching between them based on signal strength, the patent uses a single non-linear amplifier that continuously adapts its gain. This inverts the problem-solving strategy from discrete mode switching to continuous adaptive adjustment, reducing complexity while maintaining precision.
3Reliability
If the amplification factor is increased to detect weak signals from distant or low-reflectivity targets, then the signal-to-noise ratio improves, but strong signals from close or high-reflectivity targets cause amplifier saturation
Solution Approach 1:
The patent applies parameter changes by making the amplification factor signal-dependent rather than constant. The amplifier dynamically adjusts its gain parameter based on the instantaneous signal amplitude, applying high gain to weak signals and low gain to strong signals. This continuous parameter adaptation prevents saturation while maintaining sensitivity, resolving the contradiction between detecting weak signals and handling strong signals within the same system.
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
This solution enhances the dynamic range of detected light intensity, simplifies calibration, and reduces the number of necessary operating modes, allowing for accurate distance measurement across a wide range of target reflectivities and distances with fewer calibration parameters.
Implementation Method 1
The reflected optical radiation is converted into an electrical reception signal by a photosensitive element in the device
Data Source
AI summary
The EDM measuring device (99) has a conditioning unit (2) including an amplifier stage (23) and for conditioning an electrical reception signal from a receiving unit (1). The amplifier stage is designed such that it has a non-linear input-output characteristic, in particular with a gain factor dependent on an amplitude value of the reception signal, and specifically with a first gain factor for a first amplitude value of the input signal and at least one second gain factor, different from the first, for a second amplitude value of the input signal. Independent claims are also included for the following: (1) a distance measuring method; (2) a method for extending the detectable amplitude dynamic range of a receiving unit of an electro-optical distance measuring device; and (3) a non-transitory computer readable medium comprising program code for carrying out a distance measuring method.