Tunable Filter Receiver for LiDAR Group Delay Distortion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laser range finding systems face challenges with group delay responses and peaking issues in time of flight applications, which affect the quality of distance detection and estimation due to mismatched tolerances in discrete components of low pass filters and the need for high fidelity pulses before analog-to-digital conversion.
Innovation Solution
A receiver for light detection and ranging systems that includes a tunable filter integrated with a transimpedance amplifier on a single integrated circuit, allowing for adjustable frequency response and reduced group delay distortion, comprising adjustable components like capacitors and resistors to minimize peaking and overshoot, and capable of filtering noise effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discrete components of low pass filters are used, then the filter can be implemented, but tolerance mismatches cause group delay distortion and peaking
Solution Approach 1:
The patent integrates the low pass filter and transimpedance amplifier into a single integrated circuit device, eliminating the need for discrete components. This integration resolves the tolerance mismatch problem by ensuring consistent electrical characteristics across all filter components, thereby eliminating group delay distortion and peaking issues that arise from discrete component variations.
Solution Approach 2:
The patent implements a tunable filter with adjustable cutoff frequency and quality factor parameters. By making these parameters可调 (adjustable), the system can optimize performance for different operating conditions while maintaining consistent electrical characteristics through integration, thus resolving the contradiction between reliable filter performance and manufacturing precision limitations of discrete components.
2Adaptability or versatility
If a fixed frequency response filter is used, then the circuit is simpler, but it cannot adapt to different operating conditions
Solution Approach 1:
The patent implements a tunable filter where the cutoff frequency and quality factor can be dynamically adjusted based on operating conditions. This dynamic capability allows the filter to adapt to different signal characteristics and noise conditions while maintaining a relatively simple integrated circuit implementation, thus resolving the contradiction between adaptability and device complexity.
3Object-affected harmful factors
If noise filtering is aggressive, then noise performance improves, but signal fidelity and group delay flatness deteriorate
Solution Approach 1:
The patent implements a tunable quality factor that allows optimization of the balance between noise filtering and signal fidelity. By adjusting the quality factor parameter, the system can achieve aggressive noise filtering when needed while maintaining signal fidelity and group delay flatness when required, thus resolving the contradiction between noise performance and signal quality.
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 solution provides enhanced noise performance and maintains signal integrity with a flat group delay response, improving the accuracy of distance detection and estimation in laser range finding systems by reducing aliasing and undershoots, and enabling the use of a wider range of photodiodes with high fidelity pulses.
Implementation Method 1
an optoelectrical device to receive a light pulse reflected from a target and to convert the light pulse to a current pulse
Data Source
AI summary
A receiver for a light detection and range finding system is disclosed. The receiver can include an optoelectrical device to receive a pulse of light reflected from a target and to convert the pulse of light to a current pulse. The receiver can also include a transimpedance amplifier (TIA) to convert the current pulse to a voltage pulse. The receiver can also include a tunable filter that has an input coupled to an output of the TIA. The tunable filter can have a frequency response that is adjustable. The TIA and the tunable filter can be disposed on a single integrated circuit (IC) die.